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1. Crystal-orientation-dependent physical sputtering from four elemental metals

Author: M. Balden, K. Schlueter, D. Dhard, P. Bauer, R. Nilsson, F. Granberg, K. Nordlund, and G. Hobler
Subjects: Physical sputtering yield, Crystallinity, Electron backscattering diffraction (EBSD), Focused ion beam (FIB), Molecular dynamics (MD) simulations, Binary collision approximation (BCA) simulations, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Physical sputtering and its dependence on crystal orientation is well-known, but crystallinity of the target is neither commonly considered in simulations nor when publishing experimental values for its yield. Due to the recent development of detector technology and therefore of crystal orientation mapping, a measuring technique has been established to obtain the physical sputtering yield for an extensive number of orientations of polycrystalline specimens. In this work, yields for two bcc metals (W and Mo) and two fcc metals (Cu and Pt) for impacting Ga ions with 30 keV and around 5 keV energy were determined experimentally and are compared with molecular dynamics (MD) simulations in a recently established two level approach and with binary collision approximation (BCA) simulations. The agreement between experimental yields and simulations is excellent regarding distribution in the angular space and reasonable regarding absolute values. As expected, the variation in angular space among the materials with the same crystal lattice structure is minor.
Published: 2023
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2. FIB line marking as a tool for local erosion/deposition/fuzz formation measurements in ASDEX Upgrade during the He campaign

Author: M. Rasiński, S. Brezinsek, A. Kreter, T. Dittmar, K. Krieger, M. Balden, P. de Marne, R. Dux, M. Faitsch, A. Hakola, J. Likonen, E. Tsitrone, and V. Rohde
Subjects: FIB line marking, W fuzz He plasma, ASDEX Upgrade, Microstructure, Erosion and re-deposition, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Tungsten (W) is the prime candidate for the plasma facing material in present and future fusion devices. When exposed to a plasma containing He ions, W can exhibit creation of sub-surface nano-bubbles leading to formation of nano-tendrils called fuzz. Formation of W fuzz was confirmed by many laboratory experiments including He loading in linear plasma devices. There is, however, limited experience related to the parameter space for fuzz formation and re-erosion in a tokamak environment. For this reason, a dedicated experiment was carried out in ASDEX Upgrade (AUG) during its 2022 He campaign to study the evolution of fuzz-like W structures.Twelve tungsten samples were mechanically polished to a mirror-like surface finish. Six of them were subsequently exposed to a He plasma in the PSI-2 linear device in order to establish a fuzz layer with a thickness of 600 – 800 nm. Before exposure in AUG, all samples were pre-characterized by Focused Ion Beam (FIB) cross-sectioning. In total 48 FIB cross-sections with line markings for quantification of local erosion, deposition and fuzz formation were prepared – 4 on each sample. The samples were placed in two parallel poloidal rows spanning a range of 20 cm around the outer strike line position (OSP). They were subsequently exposed in AUG to a series of 14 consecutive discharges, 8 in H-mode and 6 in L-mode.Detailed analysis by means of electron microscopy revealed on the samples regions of erosion, deposition and fuzz formation. Below the H-mode OSP, homogeneous co-deposits containing W and O, with a thickness up to 400 nm, were found. In the close vicinity of the H-mode OSP, significant erosion of pre-exposure PSI-2 fuzz was observed. The erosion reached up to 100 – 250 nm, depending on the location. In addition, the initially polished samples did not show any newly formed fuzz in that zone. Above the H-mode OSP, new fuzz was formed with a thickness of up to 1 μm. There was no Mo found in the newly formed fuzz. Pre-exposure PSI-2 fuzz was either removed or modified.
Published: 2023
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3. Design and GLADIS testing of a liquid tin divertor module prior to exposure in ASDEX Upgrade

Author: J.G.A. Scholte, M. Balden, B. Böswirth, S. Elgeti, H. Greuner, A. Herrmann, K. Hunger, K. Krieger, P. Leitenstern, A. Manhard, R. Neu, R.C. van Schaik, V. Rohde, I. Zammuto, and T.W. Morgan
Subjects: Liquid metal, Divertor, Tin, GLADIS, Selective laser melting, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Using liquid metals confined in capillary porous structures (CPSs) as a plasma-facing component (PFC) could prolong the lifetime of the divertor in the high heat flux area. However, the high atomic number of tin (Sn) limits its acceptable fraction in the main plasma. Therefore, a crucial step in developing this concept is to test it in a tokamak environment, particularly in the diverted plasma region, e.g. ASDEX Upgrade (AUG). In this paper, the design of liquid tin module (LTM) is explained, and the testing in the high heat flux device GLADIS before its use in AUG is presented. The LTM was additively manufactured using selective laser melting, consisting of a 1.5mm porous layer tungsten (W) directly attached to a solid W bulk. The LTM has a plasma-facing area of 16×40mm2 and was filled with 1.54g of Sn. In GLADIS, the module was exposed to power loads between 2 and 8MWm−2 for 1 up to 10s, first unfilled and later filled with Sn. The surface temperature was monitored with infrared imaging and pyrometry. The thermal response was used to compare with simulations in Ansys Mechanical, enabling a determination of the module’s effective thermal properties. Sn droplets could be observed on the infrared camera, until a surface temperature of about a 1000°C was reached. The enhanced wetting of tin on the plasma-facing surface, which was observed by a visible camera, suggests that there is a conditioning of the surface, possibly due to the removal of impurities and oxides. Subsequent examinations of the adjacent tile revealed minor Sn leakages emanating from the module’s edge. Furthermore, the module showed no indication of mechanical failure. Therefore, these results indicated that the LTM qualifies for the heat fluxes expected in ASDEX Upgrade.
Published: 2023
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4. Performance of a liquid Sn divertor target during ASDEX upgrade L-mode and H-mode operation

Author: J.G.A. Scholte, M. Balden, D. Brida, J. Cecrdle, R. Dux, S. Elgeti, M. Faitsch, A. Herrmann, J. Horacek, K. Hunger, K. Krieger, A. Manhard, P. de Marné, V. Rohde, and T.W. Morgan
Subjects: ASDEX upgrade, Liquid metal, Divertor, Tin, Impurity radiation, Nuclear engineering. Atomic power, TK9001-9401
Abstract: One of the ways to extend the lifetime of the divertor for DEMO could be to replace the solid tungsten plasma-facing components with liquid tin (Sn) confined in a tungsten capillary porous structure (CPS). Testing a CPS in a divertor plasma configuration is crucial for the development of a liquid metal divertor (LMD) to understand how the main plasma is affected. Only a limited Sn concentration is allowed in the plasma core, due to the high radiative losses associated with the high atomic number of Sn (50). Therefore, it is necessary to test a small-scale LMD filled with Sn in a tokamak environment, which has not previously been done. In ASDEX Upgrade, a liquid tin module (LTM) has been exposed by means of the divertor manipulator. During plasma flat-top, the outer strike point (OSP) was placed onto the pre-heated LTM and held there for a time interval between 2 and 3.4s over multiple discharges. Photographs of the LTM taken after each discharge, revealed macroscopic Sn leakage onto the adjacent tile. Simulations with the HeatLMD code predicted an acceptable tin erosion near the LTM with thermal sputtering dominating over evaporation. However, spectroscopic measurements revealed an order of magnitude higher erosion. Since this remained constant when the OSP was held on the LTM so that the surface temperature increased, evaporation could be excluded as the main source of Sn erosion. Comparison between discharges with different durations of OSP location on the LTM revealed an increase in core radiation up to 1.5MW due to Sn. The 1.5D-impurity transport code STRAHL was used to interpret this increase in total plasma radiation and revealed a Sn concentration in the main plasma of up to 1.4×10-4. Given that the LTM only covered about 1/650 of the outer divertor circumference, extrapolating to a full toroidal divertor implies erosion is above acceptable limits. The unexpectedly high Sn fraction in the main plasma is attributed to the ejection of Sn droplets reaching the main plasma, which may have originated from either the CPS or leaked tin. This conclusion is also supported by splashes of tin droplets, which were observed on the adjacent divertor tile and one ∼0.5m downstream. Therefore, to make a Sn-filled LMD a viable alternative to solid tungsten, the formation of droplets must be reduced by two orders of magnitude.
Published: 2023
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5. WEST full tungsten operation with an ITER grade divertor

Author: J. Bucalossi, A. Ekedahl, and the WEST Team, J. Achard, K. Afonin, O. Agullo, T. Alarcon, L. Allegretti, F. Almuhisen, H. Ancher, G. Antar, Y. Anquetin, S. Antusch, V. Anzallo, C. Arnas, J.F. Artaud, M.H. Aumeunier, S.G. Baek, X.Y. Bai, M. Balden, C. Balorin, T. Barbui, A. Barbuti, J. Barlerin, J. Barra, V. Basiuk, T. Batal, O. Baulaigue, A. Bec, M. Becoulet, E. Benoit, E. Bernard, J.M. Bernard, M. Bernert, N. Bertelli, E. Bertrand, P. Beyer, J. Bielecki, P. Bienvenu, R. Bisson, B. Bliewert, G. Bodner, S. Bose, C. Bottereau, C. Bouchand, Y. Boumendjel, F. Bouquey, C. Bourdelle, J. Bourg, S. Brezinsek, F. Brochard, C. Brun, V. Bruno, H. Bufferand, A. Bureau, S. Burles, Y. Camenen, B. Cantone, E. Caprin, M. Carole, S. Carpentier-Chouchana, G. Caulier, F. Causa, N. Cazanave, N. Chanet, O. Chellai, Y. Chen, M. Chernyshova, P. Chmielewski, W. Choe, A. Chomiczewska, G. Ciraolo, F. Clairet, J. Coenen, L. Colas, G. Colledani, J. Colnel, P. Coquillat, E. Corbel, Y. Corre, X. Courtois, T. Czarski, A. Da Ros, R. Daniel, J. Daumas, M. De Combarieu, P. De Vries, C. Dechelle, F. Deguara, R. Dejarnac, J.M. Delaplanche, L.F. Delgado-Aparicio, E. Delmas, L. Delpech, C. Desgranges, P. Devynck, J. Denis, S. Di Genova, R. Diab, A. Diallo, M. Diez, G. Dif-Pradalier, M. Dimitrova, R. Ding, T. Dittmar, L. Doceul, M. Domenes, D. Donovan, D. Douai, L. Dubus, N. Dumas, R. Dumont, F. Durand, A. Durif, F. Durodié, D. Elbeze, S. Ertmer, A. Escarguel, F. Escourbiac, B. Esposito, K. Ezato, F. Faisse, J.L. Farjon, N. Faure, N. Fedorczak, P. Fejoz, F. Felici, C. Fenzi-Bonizec, F. Ferlay, L. Ferrand, L. Fevre, M. Firdaouss, L. Fleury, D. Flouquet, T. Fonghetti, A. Gallo, X. Garbet, J. Garcia, J.L. Gardarein, L. Gargiulo, P. Garibaldi, S. Garitta, J. Gaspar, E. Gauthier, S. Gazzotti, F. Gely, J. Gerardin, G. Gervasini, E. Geulin, M. Geynet, P. Ghendrih, I. Giacalone, C. Gil, S. Ginoux, S. Girard, E. Giroux, G. Giruzzi, M. Goniche, V. Gorse, T. Gray, E. Grelier, C. Grisolia, A. Grosjean, A. Grosman, O. Grover, D. Guibert, D. Guilhem, C. Guillemaut, B. Guillermin, R. Guirlet, J.P. Gunn, Y. Gunsu, T. Gyergyek, S. Hacquin, A. Hakola, J. Harris, J.C. Hatchressian, W. Helou, P. Hennequin, C. Hernandez, L. Hijazi, J. Hillairet, T. Hirai, G.T. Hoang, C. Honoré, M. Houry, A. Huart, G. Huijsmans, P. Huynh, M. Iafrati, F. Imbeaux, N. Imbert, I. Ivanova-Stanik, P. Ivanova, R. Jalageas, A. Jamann, C. Jammes, A. Jardin, L. Jaubert, G. Jiolat, E. Joffrin, C. Johnson, A. Jonas, A. Kirschner, C.C. Klepper, M. Komm, M. Koubiti, S. Kosslow, J. Kovacic, M. Kozeiha, K. Krieger, K. Krol, I. Kudashev, B. Lacroix, L. Laguardia, V. Lamaison, V. Lapleigne, H. Laqua, C. Lau, Y. Lausenaz, R. Lé, M. Le Bohec, N. Lefevre, N. Lemoine, E. Lerche, Y. Lesourd, L. Letellier, M. Lewerentz, Y. Li, A. Liang, P. Linczuk, C. Linsmeier, M. Lipa, X. Litaudon, X. Liu, J. Llorens, T. Loarer, A. Loarte, T. Loewenhoff, G. Lombard, J. Lore, P. Lorenzetto, B. Lu, A. Lumsdaine, R. Lunsford, T. Lunt, G. Luo, P. Magaud, P. Maget, J.F. Mahieu, P. Maini, P. Malard, K. Malinowski, P. Manas, L. Manenc, V. Maquet, Y. Marandet, C. Martin, E.J. Martin, P. Martino, M. Mayer, D. Mazon, S. Mazzi, P. Messina, L. Meunier, D. Midou, G. Miglionico, Y. Mineo, M. Missirlian, R. Mitteau, B. Mitu, D. Moiraf, P. Mollard, G. Momparler, V. Moncada, T. Mondiere, C. Monti, J. Morales, M. Moreau, Ph. Moreau, Y. Moudden, G. Moureau, D. Mouyon, M. Muraglia, T. Nakano, E. Nardon, A. Neff, F. Nespoli, J. Nichols, L. Nicolas, S. Nicollet, R. Nouailletas, M. Ono, V. Ostuni, O. Paillat, C. Parish, H. Park, H. Parrat, J.Y. Pascal, B. Pegourie, F.P. Pellissier, Y. Peneliau, M. Peret, E. Pignoly, G. Pintsuk, R. Pitts, C. Pocheau, A. Podolnik, C. Portafaix, M. Poulos, P. Prochet, A. Puig Sitjes, R. Ragona, M. Rasinski, S. Ratynskaia, G. Raup, X. Regal-Mezin, C. Reux, J. Rice, M. Richou, F. Rigollet, N. Rivals, H. Roche, S. Rodrigues, J. Romazanov, G. Ronchi, C. Ruset, R. Sabot, A. Saille, R. Sakamoto, B. Salamon, F. Samaille, A. Santagiustina, B. Santraine, Y. Sarazin, O. Sauter, Y. Savoie-Peysson, L. Schiesko, M. Scholz, J.L. Schwob, E. Serre, H. Shin, S. Shiraiwa, Ja. Signoret, O. Skalli-Fettachi, P. Sogorb, Y. Song, A. Spring, P. Spuig, S. Sridhar, B. Stratton, C. Talatizi, P. Tamain, R. Tatali, Q. Tichit, A. Torre, L. Toulouse, W. Treutterer, E. Tsitrone, E.A. Unterberg, G. Urbanczyk, G. Van Rooij, N. Varadarajan, S. Vartanian, E. Velly, J.M. Verger, L. Vermare, D. Vezinet, N. Vignal, B. Vincent, S. Vives, D. Volpe, G. Wallace, E. Wang, L. Wang, Y. Wang, Y.S. Wang, T. Wauters, D. Weldon, B. Wirth, M. Wirtz, A. Wojenski, M. Xu, Q.X. Yang, H. Yang, B. Zago, R. Zagorski, B. Zhang, X.J. Zhang, X.L. Zou, and the EUROfusion Tokamak Exploitation Team
Subjects: nuclear fusion, magnetic confinement, tokamak, divertor, WEST, ITER, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: The mission of WEST (tungsten-W Environment in Steady-state Tokamak) is to explore long pulse operation in a full tungsten (W) environment for preparing next-step fusion devices (ITER and DEMO) with a focus on testing the ITER actively cooled W divertor in tokamak conditions. Following the successful completion of phase 1 (2016-2021), phase 2 started in December 2022 with the lower divertor made entirely of actively cooled ITER-grade tungsten mono-blocks. A boronization prior the first plasma attempt allowed for a smooth startup with the new divertor. Despite the reduced operating window due to tungsten, rapid progress has been made in long pulse operation, resulting in discharges with a pulse length of 100 s and an injected energy of around 300 MJ per discharge. Plasma startup studies were carried out with equatorial boron nitride limiters to compare them with tungsten limiters, while Ion Cyclotron Resonance Heating assisted startup was attempted. High fluence operation in attached regime, which was the main thrust of the first campaigns, already showed the progressive build up of deposits and appearance of dust, impacting the plasma operation as the plasma fluence increased. In total, the cumulated injected energy during the first campaigns reached 43 GJ and the cumulated plasma time exceeded 5 h. Demonstration of controlled X-Point Radiator regime is also reported, opening a promising route for investigating plasma exhaust and plasma-wall interaction issues in more detached regime. This paper summarises the lessons learned from the manufacturing and the first operation of the ITER-grade divertor, describing the progress achieved in optimising operation in a full W environment with a focus on long pulse operation and plasma wall interaction.
Published: 2024
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6. Metallic melt transport across castellated tiles

Author: S. Ratynskaia, K. Paschalidis, K. Krieger, L. Vignitchouk, P. Tolias, M. Balden, M. Faitsch, V. Rohde, Y. Corre, R.A. Pitts, the ASDEX Upgrade Team, and the EUROfusion MST1 Team
Subjects: tungsten melting, melt edge wetting, melt gap bridging, large-scale melt motion, MEMENTO code, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: In future fusion reactors, extended melt pools in combination with strong plasma-induced accelerations, suggest that the metallic melt could reach the gaps between castellated plasma-facing components, potentially accompanied by profound changes in their mechanical response. The first results of a combined experimental and modelling effort to elucidate the physics of melt transport across gaps are presented. Transient melting of specially designed tungsten samples featuring toroidal gaps has been achieved in ASDEX Upgrade providing direct evidence of gap bridging. Detailed modelling with the MEMENTO melt dynamics code is reported. Empirical evidence and simulations reveal that the presence of gaps can be safely ignored in macroscopic melt motion predictions as well as that the re-solidification limited melt spreading facilitates gap bridging and leads to poor melt attachment. The findings are discussed in the context of ITER and DEMO.
Published: 2024
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7. Overview of ASDEX upgrade results in view of ITER and DEMO

Author: H. Zohm, E. Alessi, C. Angioni, N. Arden, V. Artigues, M. Astrain, O. Asunta, M. Balden, V. Bandaru, A. Banon Navarro, M. Bauer, A. Bergmann, M. Bergmann, J. Bernardo, M. Bernert, A. Biancalani, R. Bielajew, R. Bilato, G. Birkenmeier, T. Blanken, V. Bobkov, A. Bock, L. Bock, T. Body, T. Bolzonella, N. Bonanomi, A. Bortolon, B. Böswirth, C. Bottereau, A. Bottino, H. van den Brand, M. Brenzke, S. Brezinsek, D. Brida, F. Brochard, J. Buchanan, A. Buhler, A. Burckhart, Y. Camenen, B. Cannas, P. Cano Megías, D. Carlton, M. Carr, P. Carvalho, C. Castaldo, A. Castillo Castillo, A. Cathey, M. Cavedon, C. Cazzaniga, C. Challis, A. Chankin, A. Chomiczewska, C. Cianfarani, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, L. Colas, G. Conway, S. Costea, D. Coster, T. Cote, A.J. Creely, G. Croci, D.J. Cruz Zabala, G. Cseh, I. Cziegler, O. D’Arcangelo, A. Dal Molin, P. David, C. Day, M. de Baar, P. de Marné, R. Delogu, P. Denner, A. Di Siena, M. Dibon, J.J. Dominguez-Palacios Durán, D. Dunai, M. Dreval, M. Dunne, B.P. Duval, R. Dux, T. Eich, S. Elgeti, A. Encheva, B. Esposito, E. Fable, M. Faitsch, D. Fajardo Jimenez, U. Fantz, M. Farnik, H. Faugel, F. Felici, O. Ficker, A. Figueredo, R. Fischer, O. Ford, L. Frassinetti, M. Fröschle, G. Fuchert, J.C. Fuchs, H. Fünfgelder, S. Futatani, K. Galazka, J. Galdon-Quiroga, D. Gallart Escolà, A. Gallo, Y. Gao, S. Garavaglia, M. Garcia Muñoz, B. Geiger, L. Giannone, S. Gibson, L. Gil, E. Giovannozzi, I. Girka, O. Girka, T. Gleiter, S. Glöggler, M. Gobbin, J.C. Gonzalez, J. Gonzalez Martin, T. Goodman, G. Gorini, T. Görler, D. Gradic, G. Granucci, A. Gräter, G. Grenfell, H. Greuner, M. Griener, M. Groth, O. Grover, A. Gude, L. Guimarais, S. Günter, D. Hachmeister, A.H. Hakola, C. Ham, T. Happel, N. den Harder, G. Harrer, J. Harrison, V. Hauer, T. Hayward-Schneider, B. Heinemann, P. Heinrich, T. Hellsten, S. Henderson, P. Hennequin, M. Herschel, S. Heuraux, A. Herrmann, E. Heyn, F. Hitzler, J. Hobirk, K. Höfler, S. Hörmann, J.H. Holm, M. Hölzl, C. Hopf, L. Horvath, T. Höschen, A. Houben, A. Hubbard, A. Huber, K. Hunger, V. Igochine, M. Iliasova, J. Illerhaus, K. Insulander Björk, C. Ionita-Schrittwieser, I. Ivanova-Stanik, S. Jachmich, W. Jacob, N. Jaksic, A. Jansen van Vuuren, F. Jaulmes, F. Jenko, T. Jensen, E. Joffrin, A. Kallenbach, J. Kalis, A. Kappatou, J. Karhunen, C.-P. Käsemann, S. Kasilov, Y. Kazakov, A. Kendl, W. Kernbichler, E. Khilkevitch, M. Kircher, A. Kirk, S. Kjer Hansen, V. Klevarova, F. Klossek, G. Kocsis, M. Koleva, M. Komm, M. Kong, A. Krämer-Flecken, M. Krause, I. Krebs, A. Kreuzeder, K. Krieger, O. Kudlacek, D. Kulla, T. Kurki-Suonio, B. Kurzan, B. Labit, K. Lackner, F. Laggner, A. Lahtinen, P. Lainer, P.T. Lang, P. Lauber, M. Lehnen, L. Leppin, E. Lerche, N. Leuthold, L. Li, J. Likonen, O. Linder, H. Lindl, B. Lipschultz, Y. Liu, Z. Lu, T. Luda Di Cortemiglia, N.C. Luhmann, T. Lunt, A. Lyssoivan, T. Maceina, J. Madsen, A. Magnanimo, H. Maier, J. Mailloux, R. Maingi, O. Maj, E. Maljaars, V. Maquet, A. Mancini, A. Manhard, P. Mantica, M. Mantsinen, P. Manz, M. Maraschek, C. Marchetto, M. Markl, L. Marrelli, P. Martin, F. Matos, M. Mayer, P.J. McCarthy, R. McDermott, G. Meng, R. Merkel, A. Merle, H. Meyer, M. Michelini, D. Milanesio, V. Mitterauer, P. Molina Cabrera, M. Muraca, F. Nabais, V. Naulin, R. Nazikian, R.D. Nem, R. Neu, A.H. Nielsen, S.K. Nielsen, T. Nishizawa, M. Nocente, I. Novikau, S. Nowak, R. Ochoukov, J. Olsen, P. Oyola, O. Pan, G. Papp, A. Pau, G. Pautasso, C. Paz-Soldan, M. Peglau, E. Peluso, P. Petersson, C. Piron, U. Plank, B. Plaum, B. Plöckl, V. Plyusnin, G. Pokol, E. Poli, A. Popa, L. Porte, J. Puchmayr, T. Pütterich, L. Radovanovic, M. Ramisch, J. Rasmussen, G. Ratta, S. Ratynskaia, G. Raupp, A. Redl, D. Réfy, M. Reich, F. Reimold, D. Reiser, M. Reisner, D. Reiter, B. Rettino, T. Ribeiro, D. Ricci, R. Riedl, J. Riesch, J.F. Rivero Rodriguez, G. Rocchi, P. Rodriguez-Fernandez, V. Rohde, G. Ronchi, M. Rott, M. Rubel, D.A. Ryan, F. Ryter, S. Saarelma, M. Salewski, A. Salmi, O. Samoylov, L. Sanchis Sanchez, J. Santos, O. Sauter, G. Schall, A. Schlüter, J. Scholte, K. Schmid, O. Schmitz, P.A. Schneider, R. Schrittwieser, M. Schubert, C. Schuster, N. Schwarz, T. Schwarz-Selinger, J. Schweinzer, F. Sciortino, O. Seibold-Benjak, A. Shabbir, A. Shalpegin, S. Sharapov, U. Sheikh, A. Shevelev, G. Sias, M. Siccinio, B. Sieglin, A. Sigalov, A. Silva, C. Silva, D. Silvagni, J. Simpson, S. Sipilä, A. Snicker, E. Solano, C. Sommariva, C. Sozzi, M. Spacek, G. Spizzo, M. Spolaore, A. Stegmeir, M. Stejner, D. Stieglitz, J. Stober, U. Stroth, E. Strumberger, G. Suarez Lopez, W. Suttrop, T. Szepesi, B. Tál, T. Tala, W. Tang, G. Tardini, M. Tardocchi, D. Terranova, M. Teschke, E. Thorén, W. Tierens, D. Told, W. Treutterer, G. Trevisan, M. Tripský, P. Ulbl, G. Urbanczyk, M. Usoltseva, M. Valisa, M. Valovic, S. van Mulders, M. van Zeeland, F. Vannini, B. Vanovac, P. Varela, S. Varoutis, T. Verdier, G. Verdoolaege, N. Vianello, J. Vicente, T. Vierle, E. Viezzer, I. Voitsekhovitch, U. von Toussaint, D. Wagner, X. Wang, M. Weiland, D. Wendler, A.E. White, M. Willensdorfer, B. Wiringer, M. Wischmeier, R. Wolf, E. Wolfrum, Q. Yang, C. Yoo, Q. Yu, R. Zagórski, I. Zammuto, T. Zehetbauer, W. Zhang, W. Zholobenko, A. Zibrov, M. Zilker, C.F.B. Zimmermann, A. Zito, S. Zoletnik, the EUROfusion Tokamak Exploitation Team, and the ASDEX Upgrade Team
Subjects: tokamak, MHD stability, transport modelling, radiative exhaust, disruption physics, ELM free scenarios, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER and EU DEMO. A major objective of the AUG programme is to shed light on the underlying physics of confinement, stability, and plasma exhaust in order to allow reliable extrapolation of results obtained on present day machines to these reactor-grade devices. Concerning pedestal physics, the mitigation of edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found to be consistent with a reduction of the linear peeling-ballooning stability threshold due to the helical deformation of the plasma. Conversely, ELM suppression by RMPs is ascribed to an increased pedestal transport that keeps the plasma away from this boundary. Candidates for this increased transport are locally enhanced turbulence and a locked magnetic island in the pedestal. The enhanced D-alpha (EDA) and quasi-continuous exhaust (QCE) regimes have been established as promising ELM-free scenarios. Here, the pressure gradient at the foot of the H-mode pedestal is reduced by a quasi-coherent mode, consistent with violation of the high-n ballooning mode stability limit there. This is suggestive that the EDA and QCE regimes have a common underlying physics origin. In the area of transport physics, full radius models for both L- and H-modes have been developed. These models predict energy confinement in AUG better than the commonly used global scaling laws, representing a large step towards the goal of predictive capability. A new momentum transport analysis framework has been developed that provides access to the intrinsic torque in the plasma core. In the field of exhaust, the X-Point Radiator (XPR), a cold and dense plasma region on closed flux surfaces close to the X-point, was described by an analytical model that provides an understanding of its formation as well as its stability, i.e., the conditions under which it transitions into a deleterious MARFE with the potential to result in a disruptive termination. With the XPR close to the divertor target, a new detached divertor concept, the compact radiative divertor, was developed. Here, the exhaust power is radiated before reaching the target, allowing close proximity of the X-point to the target. No limitations by the shallow field line angle due to the large flux expansion were observed, and sufficient compression of neutral density was demonstrated. With respect to the pumping of non-recycling impurities, the divertor enrichment was found to mainly depend on the ionisation energy of the impurity under consideration. In the area of MHD physics, analysis of the hot plasma core motion in sawtooth crashes showed good agreement with nonlinear 2-fluid simulations. This indicates that the fast reconnection observed in these events is adequately described including the pressure gradient and the electron inertia in the parallel Ohm’s law. Concerning disruption physics, a shattered pellet injection system was installed in collaboration with the ITER International Organisation. Thanks to the ability to vary the shard size distribution independently of the injection velocity, as well as its impurity admixture, it was possible to tailor the current quench rate, which is an important requirement for future large devices such as ITER. Progress was also made modelling the force reduction of VDEs induced by massive gas injection on AUG. The H-mode density limit was characterised in terms of safe operational space with a newly developed active feedback control method that allowed the stability boundary to be probed several times within a single discharge without inducing a disruptive termination. Regarding integrated operation scenarios, the role of density peaking in the confinement of the ITER baseline scenario (high plasma current) was clarified. The usual energy confinement scaling ITER98( p,y ) does not capture this effect, but the more recent H20 scaling does, highlighting again the importance of developing adequate physics based models. Advanced tokamak scenarios, aiming at large non-inductive current fraction due to non-standard profiles of the safety factor in combination with high normalised plasma pressure were studied with a focus on their access conditions. A method to guide the approach of the targeted safety factor profiles was developed, and the conditions for achieving good confinement were clarified. Based on this, two types of advanced scenarios (‘hybrid’ and ‘elevated’ q -profile) were established on AUG and characterised concerning their plasma performance.
Published: 2024
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8. Overview of the EUROfusion Tokamak Exploitation programme in support of ITER and DEMO

Author: E. Joffrin, M. Wischmeier, M. Baruzzo, A. Hakola, A. Kappatou, D. Keeling, B. Labit, E. Tsitrone, N. Vianello, the ASDEX Upgrade Team, JET Contributors, the MAST-U Team, the TCV Team, the WEST Team, the EUROfusion Tokamak Exploitation Team:, D. Abate, J. Adamek, M. Agostini, C. Albert, F.C.P. Albert Devasagayam, S. Aleiferis, E. Alessi, J. Alhage, S. Allan, J. Allcock, M. Alonzo, G. Anastasiou, E. Andersson Sunden, C. Angioni, Y. Anquetin, L. Appel, G.M. Apruzzese, M. Ariola, C. Arnas, J.F. Artaud, W. Arter, O. Asztalos, L. Aucone, M.H. Aumeunier, F. Auriemma, J. Ayllon, E. Aymerich, A. Baciero, F. Bagnato, L. Bähner, F. Bairaktaris, P. Balázs, L. Balbinot, I. Balboa, M. Balden, A. Balestri, M. Baquero Ruiz, T. Barberis, C. Barcellona, O. Bardsley, S. Benkadda, T. Bensadon, E. Bernard, M. Bernert, H. Betar, R. Bianchetti Morales, J. Bielecki, R. Bilato, P. Bilkova, W. Bin, G. Birkenmeier, R. Bisson, P. Blanchard, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, K. Bogar, P. Bohm, T. Bolzonella, F. Bombarda, N. Bonanomi, L. Boncagni, D. Bonfiglio, R. Bonifetto, M. Bonotto, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, C. Bowman, S. Brezinsek, D. Brida, F. Brochard, R. Brunet, D. Brunetti, V. Bruno, R. Buchholz, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, J. Cai, R. Calado, J. Caloud, S. Cancelli, F. Cani, B. Cannas, M. Cappelli, S. Carcangiu, A. Cardinali, S. Carli, D. Carnevale, M. Carole, M. Carpita, D. Carralero, F. Caruggi, I.S. Carvalho, I. Casiraghi, A. Casolari, F.J. Casson, C. Castaldo, A. Cathey, F. Causa, J. Cavalier, M. Cavedon, J. Cazabonne, M. Cecconello, L. Ceelen, A. Celora, J. Cerovsky, C.D. Challis, R. Chandra, A. Chankin, B. Chapman, H. Chen, M. Chernyshova, A.G. Chiariello, P. Chmielewski, A. Chomiczewska, C. Cianfarani, G. Ciraolo, J. Citrin, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, I.H. Coffey, C. Colandrea, L. Colas, S. Conroy, C. Contre, N.J. Conway, L. Cordaro, Y. Corre, D. Costa, S. Costea, D. Coster, X. Courtois, C. Cowley, T. Craciunescu, G. Croci, A.M. Croitoru, K. Crombe, D.J. Cruz Zabala, G. Cseh, T. Czarski, A. Da Ros, A. Dal Molin, M. Dalla Rosa, Y. Damizia, O. D’Arcangelo, P. David, M. De Angeli, E. De la Cal, E. De La Luna, G. De Tommasi, J. Decker, R. Dejarnac, D. Del Sarto, G. Derks, C. Desgranges, P. Devynck, S. Di Genova, L.E. di Grazia, A. Di Siena, M. Dicorato, M. Diez, M. Dimitrova, T. Dittmar, L. Dittrich, J.J. Domínguez Palacios Durán, P. Donnel, D. Douai, S. Dowson, S. Doyle, M. Dreval, P. Drews, L. Dubus, R. Dumont, D. Dunai, M. Dunne, A. Durif, F. Durodie, G. Durr Legoupil Nicoud, B. Duval, R. Dux, T. Eich, A. Ekedahl, S. Elmore, G. Ericsson, J. Eriksson, B. Eriksson, F. Eriksson, S. Ertmer, A. Escarguel, B. Esposito, T. Estrada, E. Fable, M. Faitsch, N. Fakhrayi Mofrad, A. Fanni, T. Farley, M. Farník, N. Fedorczak, F. Felici, X. Feng, J. Ferreira, D. Ferreira, N. Ferron, O. Fevrier, O. Ficker, A.R. Field, A. Figueiredo, N. Fil, D. Fiorucci, M. Firdaouss, R. Fischer, M. Fitzgerald, M. Flebbe, M. Fontana, J. Fontdecaba Climent, A. Frank, E. Fransson, L. Frassinetti, D. Frigione, S. Futatani, R. Futtersack, S. Gabriellini, D. Gadariya, D. Galassi, K. Galazka, J. Galdon, S. Galeani, D. Gallart, A. Gallo, C. Galperti, M. Gambrioli, S. Garavaglia, J. Garcia, M. Garcia Munoz, J. Gardarein, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, M. Gelfusa, J. Gerardin, S.N. Gerasimov, R. Gerru Miguelanez, G. Gervasini, Z. Ghani, F.M. Ghezzi, G. Ghillardi, L. Giannone, S. Gibson, L. Gil, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, T. Gleiter, M. Gobbin, V. Goloborodko, A. González Ganzábal, T. Goodman, V. Gopakumar, G. Gorini, T. Görler, S. Gorno, G. Granucci, D. Greenhouse, G. Grenfell, M. Griener, W. Gromelski, M. Groth, O. Grover, M. Gruca, A. Gude, C. Guillemaut, R. Guirlet, J. Gunn, T. Gyergyek, L. Hagg, J. Hall, C.J. Ham, M. Hamed, T. Happel, G. Harrer, J. Harrison, D. Harting, N.C. Hawkes, P. Heinrich, S. Henderson, P. Hennequin, R. Henriques, S. Heuraux, J. Hidalgo Salaverri, J. Hillairet, J.C. Hillesheim, A. Hjalmarsson, A. Ho, J. Hobirk, E. Hodille, M. Hölzl, M. Hoppe, J. Horacek, N. Horsten, L. Horvath, M. Houry, K. Hromasova, J. Huang, Z. Huang, A. Huber, E. Huett, P. Huynh, A. Iantchenko, M. Imrisek, P. Innocente, C. Ionita Schrittwieser, H. Isliker, P. Ivanova, I. Ivanova Stanik, M. Jablczynska, S. Jachmich, A.S. Jacobsen, P. Jacquet, A. Jansen van Vuuren, A. Jardin, H. Järleblad, A. Järvinen, F. Jaulmes, T. Jensen, I. Jepu, S. Jessica, T. Johnson, A. Juven, J. Kalis, J. Karhunen, R. Karimov, A.N. Karpushov, S. Kasilov, Y. Kazakov, P.V. Kazantzidis, W. Kernbichler, HT. Kim, D.B. King, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, A. Kit, T. Kiviniemi, F. Kjær, E. Klinkby, A. Knieps, U. Knoche, M. Kochan, F. Köchl, G. Kocsis, J.T.W. Koenders, L. Kogan, Y. Kolesnichenko, Y. Kominis, M. Komm, M. Kong, B. Kool, S.B. Korsholm, D. Kos, M. Koubiti, J. Kovacic, Y. Kovtun, E. Kowalska Strzeciwilk, K. Koziol, M. Kozulia, A. Krämer Flecken, A. Kreter, K. Krieger, U. Kruezi, O. Krutkin, O. Kudlacek, U. Kumar, H. Kumpulainen, M.H. Kushoro, R. Kwiatkowski, M. La Matina, M. Lacquaniti, L. Laguardia, P. Lainer, P. Lang, M. Larsen, E. Laszynska, K.D. Lawson, A. Lazaros, E. Lazzaro, M.Y.K. Lee, S. Leerink, M. Lehnen, M. Lennholm, E. Lerche, Y. Liang, A. Lier, J. Likonen, O. Linder, B. Lipschultz, A. Listopad, X. Litaudon, E. Litherland Smith, D. Liuzza, T. Loarer, P.J. Lomas, J. Lombardo, N. Lonigro, R. Lorenzini, C. Lowry, T. Luda di Cortemiglia, A. Ludvig Osipov, T. Lunt, V. Lutsenko, E. Macusova, R. Mäenpää, P. Maget, C.F. Maggi, J. Mailloux, S. Makarov, K. Malinowski, P. Manas, A. Mancini, D. Mancini, P. Mantica, M. Mantsinen, J. Manyer, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, S. Marchioni, A. Mariani, M. Marin, M. Markl, T. Markovic, D. Marocco, S. Marsden, L. Martellucci, P. Martin, C. Martin, F. Martinelli, L. Martinelli, J.R. Martin Solis, R. Martone, M. Maslov, R. Masocco, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, M.L. Mayoral, D. Mazon, S. Mazzi, C. Mazzotta, G. McArdle, R. McDermott, K. McKay, A.G. Meigs, C. Meineri, A. Mele, V. Menkovski, S. Menmuir, A. Merle, H. Meyer, K. Mikszuta Michalik, D. Milanesio, F. Militello, A. Milocco, I.G. Miron, J. Mitchell, R. Mitteau, V. Mitterauer, J. Mlynar, V. Moiseenko, P. Molna, F. Mombelli, C. Monti, A. Montisci, J. Morales, P. Moreau, J.M. Moret, A. Moro, D. Moulton, P. Mulholland, M. Muraglia, A. Murari, A. Muraro, P. Muscente, D. Mykytchuk, F. Nabais, Y. Nakeva, F. Napoli, E. Nardon, M.F. Nave, R.D. Nem, A. Nielsen, S.K. Nielsen, M. Nocente, R. Nouailletas, S. Nowak, H. Nyström, R. Ochoukov, N. Offeddu, S. Olasz, C. Olde, F. Oliva, D. Oliveira, H.J.C. Oliver, P. Ollus, J. Ongena, F.P. Orsitto, N. Osborne, R. Otin, P. Oyola Dominguez, D.I. Palade, S. Palomba, O. Pan, N. Panadero, E. Panontin, A. Papadopoulos, P. Papagiannis, G. Papp, V.V. Parail, C. Pardanaud, J. Parisi, A. Parrott, K. Paschalidis, M. Passoni, F. Pastore, A. Patel, B. Patel, A. Pau, G. Pautasso, R. Pavlichenko, E. Pawelec, B. Pegourie, G. Pelka, E. Peluso, A. Perek, E. Perelli Cippo, C. Perez Von Thun, P. Petersson, G. Petravich, Y. Peysson, V. Piergotti, L. Pigatto, C. Piron, L. Piron, A. Pironti, F. Pisano, U. Plank, B. Ploeckl, V. Plyusnin, A. Podolnik, Y. Poels, G. Pokol, J. Poley, G. Por, M. Poradzinski, F. Porcelli, L. Porte, C. Possieri, A. Poulsen, I. Predebon, G. Pucella, M. Pueschel, P. Puglia, O. Putignano, T. Pütterich, V. Quadri, A. Quercia, M. Rabinski, L. Radovanovic, R. Ragona, H. Raj, M. Rasinski, J. Rasmussen, G. Ratta, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Refy, M. Reich, H. Reimerdes, B.C.G. Reman, O. Renders, C. Reux, D. Ricci, M. Richou, S. Rienacker, D. Rigamonti, F. Rigollet, F.G. Rimini, D. Ripamonti, N. Rispoli, N. Rivals, J.F. Rivero Rodriguez, C. Roach, G. Rocchi, S. Rode, P. Rodrigues, J. Romazanov, C.F. Romero Madrid, J. Rosato, R. Rossi, G. Rubino, J. Rueda Rueda, J. Ruiz Ruiz, P. Ryan, D. Ryan, S. Saarelma, R. Sabot, M. Salewski, A. Salmi, L. Sanchis, A. Sand, J. Santos, K. Särkimäki, M. Sassano, O. Sauter, G. Schettini, S. Schmuck, P. Schneider, N. Schoonheere, R. Schramm, R. Schrittwieser, C. Schuster, N. Schwarz, F. Sciortino, M. Scotto D’Abusco, S. Scully, A. Selce, L. Senni, M. Senstius, G. Sergienko, S.E. Sharapov, R. Sharma, A. Shaw, U. Sheikh, G. Sias, B. Sieglin, S.A. Silburn, C. Silva, A. Silva, D. Silvagni, B. Simmendefeldt Schmidt, L. Simons, J. Simpson, L. Singh, S. Sipilä, Y. Siusko, S. Smith, A. Snicker, E.R. Solano, V. Solokha, M. Sos, C. Sozzi, F. Spineanu, G. Spizzo, M. Spolaore, L. Spolladore, C. Srinivasan, A. Stagni, Z. Stancar, G. Stankunas, J. Stober, P. Strand, C.I. Stuart, F. Subba, G.Y. Sun, H.J. Sun, W. Suttrop, J. Svoboda, T. Szepesi, G. Szepesi, B. Tal, T. Tala, P. Tamain, G. Tardini, M. Tardocchi, D. Taylor, G. Telesca, A. Tenaglia, A. Terra, D. Terranova, D. Testa, C. Theiler, E. Tholerus, B. Thomas, E. Thoren, A. Thornton, A. Thrysoe, Q. TICHIT, W. Tierens, A. Titarenko, P. Tolias, E. Tomasina, M. Tomes, E. Tonello, A. Tookey, M. Toscano Jiménez, C. Tsironis, C. Tsui, A. Tykhyy, M. Ugoletti, M. Usoltseva, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, SI. Valvis, M. van Berkel, D. Van Eester, S. Van Mulders, M. van Rossem, R. Vann, B. Vanovac, J. Varela Rodriguez, J. Varje, S. Vartanian, M. Vecsei, L. Velarde Gallardo, M. Veranda, T. Verdier, G. Verdoolaege, K. Verhaegh, L. Vermare, G. Verona Rinati, J. Vicente, E. Viezzer, L. Vignitchouk, F. Villone, B. Vincent, P. Vincenzi, M.O. Vlad, G. Vogel, I. Voitsekhovitch, I. Voldiner, P. Vondracek, N.M.T. VU, T. Vuoriheimo, C. Wade, E. Wang, T. Wauters, M. Weiland, H. Weisen, N. Wendler, D. Weston, A. Widdowson, S. Wiesen, M. Wiesenberger, T. Wijkamp, M. Willensdorfer, T. Wilson, A. Wojenski, C. Wuethrich, I. Wyss, L. Xiang, S. Xu, D. Yadykin, Y. Yakovenko, H. Yang, V. Yanovskiy, R. Yi, B. Zaar, G. Zadvitskiy, L. Zakharov, P. Zanca, D. Zarzoso, Y. Zayachuk, J. Zebrowski, M. Zerbini, P. Zestanakis, C. F. B. Zimmermann, M. Zlobinski, A. Zohar, V.K. Zotta, X. Zou, M. Zuin, M. Zurita, and I. Zychor
Subjects: JET, ASDEX Upgrade, MAST-U, TCV, WEST, Tokamak Exploitation Task Force, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under the auspices of a single Task Force called ‘Tokamak Exploitation’. The goal is to benefit from the complementary capabilities of each machine in a coordinated way and help in developing a scientific output scalable to future largre machines. The programme of this Task Force ensures that ASDEX Upgrade, MAST-U, TCV, WEST and JET (since 2022) work together to achieve the objectives of Missions 1 and 2 of the EUROfusion Roadmap: i) demonstrate plasma scenarios that increase the success margin of ITER and satisfy the requirements of DEMO and, ii) demonstrate an integrated approach that can handle the large power leaving ITER and DEMO plasmas. The Tokamak Exploitation task force has therefore organized experiments on these two missions with the goal to strengthen the physics and operational basis for the ITER baseline scenario and for exploiting the recent plasma exhaust enhancements in all four devices (PEX: Plasma EXhaust) for exploring the solution for handling heat and particle exhaust in ITER and develop the conceptual solutions for DEMO. The ITER Baseline scenario has been developed in a similar way in ASDEX Upgrade, TCV and JET. Key risks for ITER such as disruptions and run-aways have been also investigated in TCV, ASDEX Upgrade and JET. Experiments have explored successfully different divertor configurations (standard, super-X, snowflakes) in MAST-U and TCV and studied tungsten melting in WEST and ASDEX Upgrade. The input from the smaller devices to JET has also been proven successful to set-up novel control schemes on disruption avoidance and detachment.
Published: 2024
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9. Overview of the first Wendelstein 7-X long pulse campaign with fully water-cooled plasma facing components

Author: O. Grulke, C. Albert, J.A. Alcuson Belloso, P. Aleynikov, K. Aleynikova, A. Alonso, G. Anda, T. Andreeva, M. Arvanitou, E. Ascasibar, E. Aymerich, K. Avramidis, J.-P. Bähner, S.-G. Baek, M. Balden, J. Baldzuhn, S. Ballinger, M. Banduch, S. Bannmann, A. Bañón Navarro, L. Baylor, C.D. Beidler, M. Beurskens, C. Biedermann, G. Birkenmeier, T. Bluhm, D. Boeckenhoff, D. Boeyaert, D. Bold, M. Borchardt, D. Borodin, H.-S. Bosch, H. Bouvain, S. Bozhenkov, T. Bräuer, H. Braune, C. Brandt, S. Brezinsek, K.J. Brunner, C. Büschel, R. Bussiahn, A. Buzás, B. Buttenschoen, V. Bykov, I. Calvo, A. Cappa, F. Carovani, D. Carralero, A. Carls, B. Carvalho, D. Castaño-Bardawil, N. Chaudhary, I. Chelis, S. Chen, D. Cipciar, J.W. Coenen, G. Conway, M. Cornelissen, Y. Corre, P. Costello, K. Crombe, G. Cseh, B. Csillag, H.I. Cu Castillo, G. Czymek, H. Damm, R.J. Davies, C. Day, S. Degenkolbe, R. De Wolf, W. Dekeyser, A. Demby, P. Despontin, C.P. Dhard, A. Dinklage, F.A. d’Isa, T. Dittmar, M. Dreval, M. Drevlak, P. Drews, J. Droste, D. Dunai, C. Dyhring, P. van Eeten, E. Edlund, M. Endler, D.A. Ennis, F.J. Escoto, M.S. Espinosa, T. Estrada, D. Fehling, L. Feuerstein, J. Fellinger, Y. Feng, D.L.C. Fernando, S. Fischer, E.R. Flom, O. Ford, T. Fornal, J. Frank, H. Frerichs, G. Fuchert, G. Gantenbein, Y. Gao, K. Garcia, I. García-Cortés, J.M. García-Regaña, B. Geiger, J. Geiger, P. Geissler, M. Gerard, G. Godino-Sedano, T. Gonda, A. González, A. Goriaev, D. Gradic, M. Grahl, H. Greuner, E. Grigore, M. Gruca, J.F. Guerrero Arnaiz, V. Haak, L. van Ham, K. Hammond, B. Hamstra, X. Han, S.K. Hansen, J. Harris, D. Hartmann, D. Hathiramani, S. Hegedus, S. Heinrich, P. Helander, F. Henke, S. Henneberg, L. Henschke, M. Hirsch, U. Hoefel, K. Hoefler, S. Hoermann, K.-P. Hollfeld, A. Holtz, D. Höschen, M. Houry, J. Huang, M. Hubeny, K. Hunger, D. Hwangbo, K. Ida, Y. Igitkhanov, S. Illy, Z. Ioannidis, M. Jablczynska, S. Jablonski, B. Jabłoński, B. Jagielski, M. Jakubowski, J. Jelonnek, F. Jenko, J. Jin, A. Johansson, G. Jouniaux, S. Kajita, J.-P. Kallmeyer, U. Kamionka, W. Kasparek, C. Kawan, Ye. O. Kazakov, N. Kenmochi, W. Kernbichler, A.K. Kharwandikar, M. Khokhlov, C. Killer, A. Kirschner, R. Kleiber, C.C. Klepper, T. Klinger, J. Knauer, A. Knieps, M. Kobayashi, G. Kocsis, Y. Kolesnichenko, A. Könies, J. Kontula, P. Kornejew, S.A. Korteweg, J. Koschinsky, J. Koster, Y. Kovtun, A. Krämer-Flecken, M. Krause, T. Kremeyer, L. Krier, D.M. Kriete, M. Krychowiak, I. Ksia¸zek, M. Kubkowska, M.D. Kuczyński, D. Kulla, A. Kumar, T. Kurki-Suonio, I. Kuzmych, S. Kwak, V. Lancelotti, A. Langenberg, H. Laqua, H.P. Laqua, M.R. Larsen, S. Lazerson, C. Lechte, B. Lee, A. LeViness, M. Lewerentz, Y. Liang, L. Liao, A. Litnovsky, J. Liu, J. Loizu, R. Lopez-Cansino, L.D. Lopez Rodriguez, A. Lorenz, R. Lunsford, Y. Luo, V. Lutsenko, N. Maaziz, M. Machielsen, R. Mackenbach, D. Makowski, E. Maragkoudakis, O. Marchuk, M. Markl, S. Marsen, J. Martínez, N. Marushchenko, S. Masuzaki, D.A. Maurer, M. Mayer, K.J. McCarthy, P. McNeely, D. Medina Roque, J. Meineke, S. Meitner, S. vaz Mendes, A. Menzel-Barbara, B. van Milligen, A. Mishchenko, V. Moiseenko, A. Möller, S. Möller, D. Moseev, G. Motojima, S. Mulas, P. Mulholland, M. Nagel, D. Nagy, Y. Narbutt, D. Naujoks, P. Nelde, R. Neu, O. Neubauer, U. Neuner, D. Nicolai, S. Nielsen, C. Nührenberg, R. Ochoukov, G. Offermanns, J. Ongena, J.W. Oosterbeek, M. Otte, N. Pablant, N. Panadero Alvarez, A. Pandey, G. Partesotti, E.A. Pasch, R. Pavlichenko, E. Pawelec, T.S. Pedersen, V. Perseo, B. Peterson, F. Pisano, B. Plaum, G. Plunk, L. Podavini, N.S. Polei, P. Poloskei, S. Ponomarenko, P. Pons-Villalonga, M. Porkolab, J. Proll, M.J. Pueschel, A. Puig Sitjes, R. Ragona, K. Rahbarnia, M. Rasiński, J. Rasmussen, D. Refy, F. Reimold, M. Richou, J.S. Riemann, K. Riße, J. de la Riva Villén, G. Roberg-Clark, E. Rodriguez, V. Rohde, J. Romazanov, T. Romba, D. Rondeshagen, M. Rud, T. Ruess, T. Rummel, A. Runov, C. Ruset, N. Rust, L. Ryc, T. Rzesnicki, M. Salewski, E. Sánchez, L. Sanchis Sanchez, G. Satheeswaran, J. Schacht, E. Scharff, J. Schilling, G. Schlisio, K. Schmid, J.C. Schmitt, O. Schmitz, M. Schneider, M. Van Schoor, T. Schröder, R. Schroeder, B. Schweer, S. Sereda, B. Shanahan, G. Sias, S. Simko, L. Singh, Y. Siusko, C. Slaby, M. Śle¸czka, B.S. Smith, D.R. Smith, H. Smith, M. Spolaore, A. Spring, T. Stange, A. von Stechow, I. Stepanov, M. Stern, U. Stroth, Y. Suzuki, C. Swee, L. Syrocki, T. Szabolics, T. Szepesi, R. Takacs, H. Takahashi, N. Tamura, C. Tantos, J. Terry, S. Thiede, H. Thienpondt, H. Thomsen, M. Thumm, T. Thun, S. Togo, T. Tork, H. Trimino Mora, A. Tsikouras, Y. Turkin, L. Vano, S. Varoutis, M. Vecsei, J.L. Velasco, M. Verstraeten, M. Vervier, E. Viezzer, J. Wagner, E. Wang, F. Wang, M. Wappl, F. Warmer, T. Wegner, Y. Wei, G. Weir, N. Wendler, U. Wenzel, A. White, F. Wilms, T. Windisch, A. Winter, V. Winters, R. Wolf, G. Wurden, P. Xanthopoulos, H.M. Xiang, S. Xu, H. Yamada, J. Yang, R. Yi, M. Yokoyama, B. Zamorski, M. Zanini, M. Zarnstorff, D. Zhang, S. Zhou, J. Zhu, J. Zimmermann, A. Zocco, and S. Zoletnik
Subjects: stellarator, long-pulse operation, magnetic fusion confinement, divertor detachment, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: After a long device enhancement phase, scientific operation resumed in 2022. The main new device components are the water cooling of all plasma facing components and the new water-cooled high heat flux divertor units. Water cooling allowed for the first long-pulse operation campaign. A maximum discharge length of 8 min was achieved with a total heating energy of 1.3 GJ. Safe divertor operation was demonstrated in attached and detached mode. Stable detachment is readily achieved in some magnetic configurations but requires impurity seeding in configurations with small magnetic pitch angle within the edge islands. Progress was made in the characterization of transport mechanisms across edge magnetic islands: Measurement of the potential distribution and flow pattern reveals that the islands are associated with a strong poloidal drift, which leads to rapid convection of energy and particles from the last closed flux surface into the scrape-off layer. Using the upgraded plasma heating systems, advanced heating scenarios were developed, which provide improved energy confinement comparable to the scenario, in which the record triple product for stellarators was achieved in the previous operation campaign. However, a magnetic configuration-dependent critical heating power limit of the electron cyclotron resonance heating was observed. Exceeding the respective power limit leads to a degradation of the confinement.
Published: 2024
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10. Overview of T and D–T results in JET with ITER-like wall

Author: C.F. Maggi, D. Abate, N. Abid, P. Abreu, O. Adabonyan, M. Afzal, I. Ahmad, M. Akhtar, R. Albanese, S. Aleiferis, E. Alessi, P. Aleynikov, J. Alguacil, J. Alhage, M. Ali, H. Allen, M. Allinson, M. Alonzo, E. Alves, R. Ambrosino, E. Andersson Sundén, P. Andrew, M. Angelone, C. Angioni, I. Antoniou, L. Appel, C. Appelbee, C. Aramunde, M. Ariola, G. Arnoux, G. Artaserse, J.-F. Artaud, W. Arter, V. Artigues, F.J. Artola, A. Ash, O. Asztalos, D. Auld, F. Auriemma, Y. Austin, L. Avotina, J. Ayllón, E. Aymerich, A. Baciero, L. Bähner, F. Bairaktaris, I. Balboa, M. Balden, N. Balshaw, V.K. Bandaru, J. Banks, A. Banon Navarro, C. Barcellona, O. Bardsley, M. Barnes, R. Barnsley, M. Baruzzo, M. Bassan, A. Batista, P. Batistoni, L. Baumane, B. Bauvir, L. Baylor, C. Bearcroft, P. Beaumont, D. Beckett, A. Begolli, M. Beidler, N. Bekris, M. Beldishevski, E. Belli, F. Belli, S. Benkadda, J. Bentley, E. Bernard, J. Bernardo, M. Bernert, M. Berry, L. Bertalot, H. Betar, M. Beurskens, P.G. Bhat, S. Bickerton, J. Bielecki, T. Biewer, R. Bilato, P. Bílková, G. Birkenmeier, R. Bisson, J.P.S. Bizarro, P. Blatchford, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, G. Bodnar, P. Bohm, L. Bonalumi, N. Bonanomi, D. Bonfiglio, X. Bonnin, P. Bonofiglo, J. Booth, D. Borba, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, M. Bowden, I. Božičević Mihalić, S.C. Bradnam, B. Breizman, S. Brezinsek, D. Brida, M. Brix, P. Brown, D. Brunetti, M. Buckley, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, A. Burgess, A. Buscarino, A. Busse, D. Butcher, G. Calabrò, L. Calacci, R. Calado, R. Canavan, B. Cannas, M. Cannon, M. Cappelli, S. Carcangiu, P. Card, A. Cardinali, S. Carli, P. Carman, D. Carnevale, B. Carvalho, I.S. Carvalho, P. Carvalho, I. Casiraghi, F.J. Casson, C. Castaldo, J.P. Catalan, N. Catarino, F. Causa, M. Cavedon, M. Cecconello, L. Ceelen, C.D. Challis, B. Chamberlain, R. Chandra, C.S. Chang, A. Chankin, B. Chapman, P. Chauhan, M. Chernyshova, A. Chiariello, G.-C. Chira, P. Chmielewski, A. Chomiczewska, L. Chone, J. Cieslik, G. Ciraolo, D. Ciric, J. Citrin, Ł. Ciupinski, R. Clarkson, M. Cleverly, P. Coates, V. Coccorese, R. Coelho, J.W. Coenen, I.H. Coffey, A. Colangeli, L. Colas, J. Collins, S. Conroy, C. Contré, N.J. Conway, D. Coombs, P. Cooper, S. Cooper, L. Cordaro, C. Corradino, Y. Corre, G. Corrigan, D. Coster, T. Craciunescu, S. Cramp, D. Craven, R. Craven, G. Croci, D. Croft, K. Crombé, T. Cronin, N. Cruz, A. Cufar, A. Cullen, A. Dal Molin, S. Dalley, P. David, A. Davies, J. Davies, S. Davies, G. Davis, K. Dawson, S. Dawson, I. Day, G. De Tommasi, J. Deane, M. Dearing, M. De Bock, J. Decker, R. Dejarnac, E. Delabie, E. de la Cal, E. de la Luna, D. Del Sarto, A. Dempsey, W. Deng, A. Dennett, G.L. Derks, G. De Temmerman, F. Devasagayam, P. de Vries, P. Devynck, A. di Siena, D. Dickinson, T. Dickson, M. Diez, P. Dinca, T. Dittmar, L. Dittrich, J. Dobrashian, T. Dochnal, A.J.H. Donné, W. Dorland, S. Dorling, S. Dormido-Canto, R. Dotse, D. Douai, S. Dowson, R. Doyle, M. Dreval, P. Drews, G. Drummond, Ph. Duckworth, H.G. Dudding, R. Dumont, P. Dumortier, D. Dunai, T. Dunatov, M. Dunne, I. Ďuran, F. Durodié, R. Dux, T. Eade, E. Eardley, J. Edwards, T. Eich, A. Eksaeva, H. El-Haroun, R.D. Ellis, G. Ellwood, C. Elsmore, S. Emery, G. Ericsson, B. Eriksson, F. Eriksson, J. Eriksson, L.G. Eriksson, S. Ertmer, G. Evans, S. Evans, E. Fable, D. Fagan, M. Faitsch, D. Fajardo Jimenez, M. Falessi, A. Fanni, T. Farmer, I. Farquhar, B. Faugeras, S. Fazinić, N. Fedorczak, K. Felker, R. Felton, H. Fernandes, D.R. Ferreira, J. Ferreira, G. Ferrò, J. Fessey, O. Février, O. Ficker, A.R. Field, A. Figueiredo, J. Figueiredo, A. Fil, N. Fil, P. Finburg, U. Fischer, G. Fishpool, L. Fittill, M. Fitzgerald, D. Flammini, J. Flanagan, S. Foley, N. Fonnesu, M. Fontana, J.M. Fontdecaba, L. Fortuna, E. Fortuna-Zalesna, M. Fortune, C. Fowler, P. Fox, O. Franklin, E. Fransson, L. Frassinetti, R. Fresa, D. Frigione, T. Fülöp, M. Furseman, S. Gabriellini, D. Gadariya, S. Gadgil, K. Gál, S. Galeani, A. Galkowski, D. Gallart, M. Gambrioli, T. Gans, J. Garcia, M. García-Muñoz, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, D. Gear, T. Gebhart, S. Gee, M. Gelfusa, R. George, S.N. Gerasimov, R. Gerru, G. Gervasini, M. Gethins, Z. Ghani, M. Gherendi, P.-I. Gherghina, F. Ghezzi, L. Giacomelli, C. Gibson, L. Gil, M.R. Gilbert, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, J. Goff, V. Goloborodko, R. Gomes, J.-F. Gomez, B. Gonçalves, M. Goniche, J. Gonzalez-Martin, A. Goodyear, S. Gore, G. Gorini, T. Görler, N. Gotts, E. Gow, J.P. Graves, J. Green, H. Greuner, E. Grigore, F. Griph, W. Gromelski, M. Groth, C. Grove, R. Grove, N. Gupta, S. Hacquin, L. Hägg, A. Hakola, M. Halitovs, J. Hall, C.J. Ham, M. Hamed, M.R. Hardman, Y. Haresawa, G. Harrer, J.R. Harrison, D. Harting, D.R. Hatch, T. Haupt, J. Hawes, N.C. Hawkes, J. Hawkins, S. Hazael, J. Hearmon, P. Heesterman, P. Heinrich, M. Held, W. Helou, O. Hemming, S.S. Henderson, R. Henriques, R.B. Henriques, D. Hepple, J. Herfindal, G. Hermon, J.C. Hillesheim, K. Hizanidis, A. Hjalmarsson, A. Ho, J. Hobirk, O. Hoenen, C. Hogben, A. Hollingsworth, S. Hollis, E. Hollmann, M. Hölzl, M. Hook, M. Hoppe, J. Horáček, N. Horsten, A. Horton, L.D. Horton, L. Horvath, S. Hotchin, Z. Hu, Z. Huang, E. Hubenov, A. Huber, V. Huber, T. Huddleston, G.T.A. Huijsmans, Y. Husain, P. Huynh, A. Hynes, D. Iglesias, M.V. Iliasova, M. Imríšek, J. Ingleby, P. Innocente, V. Ioannou-Sougleridis, N. Isernia, I. Ivanova-Stanik, E. Ivings, S. Jachmich, T. Jackson, A.S. Jacobsen, P. Jacquet, H. Järleblad, A. Järvinen, F. Jaulmes, N. Jayasekera, F. Jenko, I. Jepu, E. Joffrin, T. Johnson, J. Johnston, C. Jones, E. Jones, G. Jones, L. Jones, T.T.C. Jones, A. Joyce, M. Juvonen, A. Kallenbach, P. Kalnina, D. Kalupin, P. Kanth, A. Kantor, A. Kappatou, O. Kardaun, J. Karhunen, E. Karsakos, Ye.O. Kazakov, V. Kazantzidis, D.L. Keeling, W. Kelly, M. Kempenaars, D. Kennedy, K. Khan, E. Khilkevich, C. Kiefer, H.-T. Kim, J. Kim, S.H. Kim, D.B. King, D.J. Kinna, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, T. Kiviniemi, G. Kizane, C. Klepper, A. Klix, G. Kneale, M. Knight, P. Knight, R. Knights, S. Knipe, U. Knoche, M. Knolker, M. Kocan, F. Köchl, G. Kocsis, J.T.W. Koenders, Y. Kolesnichenko, Y. Kominis, M. Kong, B. Kool, V. Korovin, S.B. Korsholm, B. Kos, D. Kos, M. Koubiti, Y. Kovtun, E. Kowalska-Strzęciwilk, K. Koziol, Y. Krasikov, A. Krasilnikov, V. Krasilnikov, M. Kresina, A. Kreter, K. Krieger, A. Krivska, U. Kruezi, I. Książek, H. Kumpulainen, B. Kurzan, S. Kwak, O.J. Kwon, B. Labit, M. Lacquaniti, A. Lagoyannis, L. Laguardia, A. Laing, V. Laksharam, N. Lam, H.T. Lambertz, B. Lane, M. Langley, E. Lascas Neto, E. Łaszyńska, K.D. Lawson, A. Lazaros, E. Lazzaro, G. Learoyd, C. Lee, K. Lee, S. Leerink, T. Leeson, X. Lefebvre, H.J. Leggate, J. Lehmann, M. Lehnen, D. Leichtle, F. Leipold, I. Lengar, M. Lennholm, E. Leon Gutierrez, L.A. Leppin, E. Lerche, A. Lescinskis, S. Lesnoj, L. Lewin, J. Lewis, J. Likonen, Ch. Linsmeier, X. Litaudon, E. Litherland-Smith, F. Liu, T. Loarer, A. Loarte, R. Lobel, B. Lomanowski, P.J. Lomas, J. Lombardo, R. Lorenzini, S. Loreti, V.P. Loschiavo, M. Loughlin, T. Lowe, C. Lowry, T. Luce, R. Lucock, T. Luda Di Cortemiglia, M. Lungaroni, C.P. Lungu, T. Lunt, V. Lutsenko, B. Lyons, J. Macdonald, E. Macusova, R. Mäenpää, H. Maier, J. Mailloux, S. Makarov, P. Manas, A. Manning, P. Mantica, M.J. Mantsinen, J. Manyer, A. Manzanares, Ph. Maquet, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, O. Marchuk, A. Mariani, G. Mariano, M. Marin, A. Marin Roldan, M. Marinelli, T. Markovič, L. Marot, C. Marren, S. Marsden, S. Marsen, J. Marsh, R. Marshall, L. Martellucci, A.J. Martin, C. Martin, R. Martone, S. Maruyama, M. Maslov, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, A. Mauriya, F. Maviglia, M. Mayer, M.-L. Mayoral, S. Mazzi, C. Mazzotta, R. McAdams, P.J. McCarthy, P. McCullen, R. McDermott, D.C. McDonald, D. McGuckin, V. McKay, L. McNamee, A. McShee, D. Mederick, M. Medland, S. Medley, K. Meghani, A.G. Meigs, S. Meitner, S. Menmuir, K. Mergia, S. Mianowski, P. Middleton, J. Mietelski, K. Mikszuta-Michalik, D. Milanesio, E. Milani, E. Militello-Asp, F. Militello, J. Milnes, A. Milocco, S. Minucci, I. Miron, J. Mitchell, J. Mlynář, V. Moiseenko, P. Monaghan, I. Monakhov, A. Montisci, S. Moon, R. Mooney, S. Moradi, R.B. Morales, L. Morgan, F. Moro, J. Morris, T. Mrowetz, L. Msero, S. Munot, A. Muñoz-Perez, M. Muraglia, A. Murari, A. Muraro, B. N’Konga, Y.S. Na, F. Nabais, R. Naish, F. Napoli, E. Nardon, V. Naulin, M.F.F. Nave, R. Neu, S. Ng, M. Nicassio, D. Nicolai, A.H. Nielsen, S.K. Nielsen, D. Nina, C. Noble, C.R. Nobs, M. Nocente, H. Nordman, S. Nowak, H. Nyström, J. O’Callaghan, M. O’Mullane, C. O’Neill, C. Olde, H.J.C. Oliver, R. Olney, J. Ongena, G.P. Orsitto, A. Osipov, R. Otin, N. Pace, L.W. Packer, E. Pajuste, D. Palade, J. Palgrave, O. Pan, N. Panadero, T. Pandya, E. Panontin, A. Papadopoulos, G. Papadopoulos, G. Papp, V.V. Parail, A. Parsloe, K. Paschalidis, M. Passeri, A. Patel, A. Pau, G. Pautasso, R. Pavlichenko, A. Pavone, E. Pawelec, C. Paz-Soldan, A. Peacock, M. Pearce, I.J. Pearson, E. Peluso, C. Penot, K. Pepperell, A. Perdas, T. Pereira, E. Perelli Cippo, C. Perez von Thun, D. Perry, P. Petersson, G. Petravich, N. Petrella, M. Peyman, L. Pigatto, M. Pillon, S. Pinches, G. Pintsuk, C. Piron, A. Pironti, F. Pisano, R. Pitts, U. Planck, N. Platt, V. Plyusnin, M. Podesta, G. Pokol, F.M. Poli, O.G. Pompilian, M. Poradzinski, M. Porkolab, C. Porosnicu, G. Poulipoulis, A.S. Poulsen, I. Predebon, A. Previti, D. Primetzhofer, G. Provatas, G. Pucella, P. Puglia, K. Purahoo, O. Putignano, T. Pütterich, A. Quercia, G. Radulescu, V. Radulovic, R. Ragona, M. Rainford, P. Raj, M. Rasinski, D. Rasmussen, J. Rasmussen, J.J. Rasmussen, A. Raso, G. Rattá, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Réfy, R. Reichle, H. Reimerdes, B.C.G. Reman, C. Reux, S. Reynolds, D. Rigamonti, E. Righi, F.G. Rimini, J. Risner, J.F. Rivero-Rodriguez, C.M. Roach, J. Roberts, R. Robins, S. Robinson, D. Robson, S. Rode, P. Rodrigues, P. Rodriguez-Fernandez, S. Romanelli, J. Romazanov, E. Rose, C. Rose-Innes, R. Rossi, S. Rowe, D. Rowlands, C. Rowley, M. Rubel, G. Rubinacci, G. Rubino, M. Rud, J. Ruiz Ruiz, F. Ryter, S. Saarelma, A. Sahlberg, M. Salewski, A. Salmi, R. Salmon, F. Salzedas, F. Sanchez, I. Sanders, D. Sandiford, F. Sanni, O. Sauter, P. Sauvan, G. Schettini, A. Shevelev, A.A. Schekochihin, K. Schmid, B.S. Schmidt, S. Schmuck, M. Schneider, P.A. Schneider, N. Schoonheere, R. Schramm, D. Scoon, S. Scully, M. Segato, J. Seidl, L. Senni, J. Seo, G. Sergienko, M. Sertoli, S.E. Sharapov, R. Sharma, A. Shaw, R. Shaw, H. Sheikh, U. Sheikh, N. Shi, P. Shigin, D. Shiraki, G. Sias, M. Siccinio, B. Sieglin, S.A. Silburn, A. Silva, C. Silva, J. Silva, D. Silvagni, D. Simfukwe, J. Simpson, P. Sirén, A. Sirinelli, H. Sjöstrand, N. Skinner, J. Slater, T. Smart, R.D. Smirnov, N. Smith, P. Smith, T. Smith, J. Snell, L. Snoj, E.R. Solano, V. Solokha, C. Sommariva, K. Soni, M. Sos, J. Sousa, C. Sozzi, T. Spelzini, F. Spineanu, L. Spolladore, D. Spong, C. Srinivasan, G. Staebler, A. Stagni, I. Stamatelatos, M.F. Stamp, Ž. Štancar, P.A. Staniec, G. Stankūnas, M. Stead, B. Stein-Lubrano, A. Stephen, J. Stephens, P. Stevenson, C. Steventon, M. Stojanov, D.A. St-Onge, P. Strand, S. Strikwerda, C.I. Stuart, S. Sturgeon, H.J. Sun, S. Surendran, W. Suttrop, J. Svensson, J. Svoboda, R. Sweeney, G. Szepesi, M. Szoke, T. Tadić, B. Tal, T. Tala, P. Tamain, K. Tanaka, W. Tang, G. Tardini, M. Tardocchi, D. Taylor, A.S. Teimane, G. Telesca, A. Teplukhina, A. Terra, D. Terranova, N. Terranova, D. Testa, B. Thomas, V.K. Thompson, A. Thorman, A.S. Thrysoe, W. Tierens, R.A. Tinguely, A. Tipton, H. Todd, M. Tomeš, A. Tookey, P. Tsavalas, D. Tskhakaya, L.-P. Turică, A. Turner, I. Turner, M. Turner, M.M. Turner, G. Tvalashvili, A. Tykhyy, S. Tyrrell, A. Uccello, V. Udintsev, A. Vadgama, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, M. Van Berkel, K.L. van de Plassche, M. van Rossem, D. Van Eester, J. Varela, J. Varje, T. Vasilopoulou, G. Vayakis, M. Vecsei, J. Vega, M. Veis, P. Veis, S. Ventre, M. Veranda, G. Verdoolaege, C. Verona, G. Verona Rinati, E. Veshchev, N. Vianello, E. Viezzer, L. Vignitchouk, R. Vila, R. Villari, F. Villone, P. Vincenzi, A. Vitins, Z. Vizvary, M. Vlad, I. Voldiner, U. Von Toussaint, P. Vondráček, B. Wakeling, M. Walker, R. Walker, M. Walsh, R. Walton, E. Wang, F. Warren, R. Warren, J. Waterhouse, C. Watts, T. Webster, M. Weiland, H. Weisen, M. Weiszflog, N. Wendler, A. West, M. Wheatley, S. Whetham, A. Whitehead, D. Whittaker, A. Widdowson, S. Wiesen, M. Willensdorfer, J. Williams, I. Wilson, T. Wilson, M. Wischmeier, A. Withycombe, D. Witts, A. Wojcik-Gargula, E. Wolfrum, R. Wood, R. Woodley, R. Worrall, I. Wyss, T. Xu, D. Yadykin, Y. Yakovenko, Y. Yang, V. Yanovskiy, R. Yi, I. Young, R. Young, B. Zaar, R.J. Zabolockis, L. Zakharov, P. Zanca, A. Zarins, D. Zarzoso Fernandez, K.-D. Zastrow, Y. Zayachuk, M. Zerbini, W. Zhang, B. Zimmermann, M. Zlobinski, A. Zocco, V.K. Zotta, M. Zuin, W. Zwingmann, and I. Zychor
Subjects: magnetic fusion, JET-ILW, D–T, tritium, alpha particles, fusion prediction, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: In 2021 JET exploited its unique capabilities to operate with T and D–T fuel with an ITER-like Be/W wall (JET-ILW). This second major JET D–T campaign (DTE2), after DTE1 in 1997, represented the culmination of a series of JET enhancements—new fusion diagnostics, new T injection capabilities, refurbishment of the T plant, increased auxiliary heating, in-vessel calibration of 14 MeV neutron yield monitors—as well as significant advances in plasma theory and modelling in the fusion community. DTE2 was complemented by a sequence of isotope physics campaigns encompassing operation in pure tritium at high T-NBI power. Carefully conducted for safe operation with tritium, the new T and D–T experiments used 1 kg of T (vs 100 g in DTE1), yielding the most fusion reactor relevant D–T plasmas to date and expanding our understanding of isotopes and D–T mixture physics. Furthermore, since the JET T and DTE2 campaigns occurred almost 25 years after the last major D–T tokamak experiment, it was also a strategic goal of the European fusion programme to refresh operational experience of a nuclear tokamak to prepare staff for ITER operation. The key physics results of the JET T and DTE2 experiments, carried out within the EUROfusion JET1 work package, are reported in this paper. Progress in the technological exploitation of JET D–T operations, development and validation of nuclear codes, neutronic tools and techniques for ITER operations carried out by EUROfusion (started within the Horizon 2020 Framework Programme and continuing under the Horizon Europe FP) are reported in (Litaudon et al Nucl. Fusion accepted), while JET experience on T and D–T operations is presented in (King et al Nucl. Fusion submitted).
Published: 2024
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11. Helium plasma operations on ASDEX Upgrade and JET in support of the non-nuclear phases of ITER

Author: A. Hakola, M. Balden, M. Baruzzo, R. Bisson, S. Brezinsek, T. Dittmar, D. Douai, M. Dunne, L. Garzotti, M. Groth, R. Henriques, L. Horvath, I. Jepu, E. Joffrin, A. Kappatou, D. Keeling, K. Krieger, B. Labit, M. Lennholm, J. Likonen, A. Loarte, P. Lomas, C. Lowry, M. Maslov, D. Matveev, R.A. Pitts, U. Plank, M. Rasinski, D. Ryan, S. Saarelma, S. Silburn, E.R. Solano, W. Suttrop, T. Tala, E. Tsitrone, N. Vianello, T. Wauters, A. Widdowson, M. Wischmeier, the EUROfusion Tokamak Exploitation Team, the ASDEX Upgrade Team, and JET Contributors
Subjects: helium plasma, H-mode, tungsten fuzz, erosion, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: For its initial operational phase, ITER has until recently considered using non-nuclear hydrogen (H) or helium (He) plasmas to keep nuclear activation at low levels. To this end, the Tokamak Exploitation Task Force of the EUROfusion Consortium carried out dedicated experimental campaigns in He on the ASDEX Upgrade (AUG) and JET tokamaks in 2022, with particular emphasis put on the ELMy H-mode operation and plasma-wall interaction processes as well as comparison to H or deuterium (D) plasmas. Both in pure He and mixed He + H plasmas, H-mode operation could be reached but more effort was needed to obtain a stable plasma scenario than in H or D. Even if the power threshold for the LH transition was lower in He, entering the type-I ELMy regime appeared to require equally much or even more heating power than in H. Suppression of ELMs by resonant magnetic perturbations was studied on AUG but was only possible in plasmas with a He content below 19%; the reason for this unexpected behaviour remains still unclear and various theoretical approaches are being pursued to properly understand the physics behind ELM suppression. The erosion rates of tungsten (W) plasma-facing components were an order of magnitude larger than what has been reported in hydrogenic plasmas, which can be attributed to the prominent role of He ^2+ ions in the plasma. For the first time, the formation of nanoscale structures (W fuzz) was unambiguously demonstrated in H-mode He plasmas on AUG. However, no direct evidence of fuzz creation on JET was obtained despite the main conditions for its occurrence being met. The reason could be a delicate balance between W erosion by ELMs, competition between the growth and annealing of the fuzz, and coverage of the surface with co-deposits.
Published: 2024
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12. Overview of plasma-tungsten surfaces interactions on the divertor test sector in WEST during the C3 and C4 campaigns

Author: M. Diez, M. Balden, S. Brezinsek, Y. Corre, N. Fedorczak, M. Firdaouss, E. Fortuna, J. Gaspar, J.P. Gunn, A. Hakola, T. Loarer, C. Martin, M. Mayer, P. Reilhac, M. Richou, E. Tsitrone, and T. Vuoriheimo
Subjects: WEST, Tungsten, Erosion and deposition, Plasma-wall interactions, Monoblocks, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Studying the ageing of tungsten monoblocks, their erosion and their fuel inventory is the priority of the WEST post-mortem analyses programme. Actively-cooled ITER-like plasma-facing units (PFUs) and special W-coated marker lower divertor tiles were retrieved from the WEST divertor after the C3 and C4 experimental campaigns to perform ex-situ analyses. The erosion/deposition pattern on the divertor was determined. The deposition is found mainly on the inner side which is covered by layered deposits that increase in thickness in the radial direction from a few hundreds of nm to a maximum of >10 µm. The deposits are mainly composed of W, O, C, B and D coming from transport of W in the vacuum chamber, oxidized layers and boronizations. Traces of Cu, Fe, Mo, Cr, Ag were also detected. A maximum deposition rate of about 1.4 nm/s was estimated while a minimum campaign-averaged net erosion rate of 0.1 nm/s was measured for the erosion markers at the strike line areas. No assessment of the erosion could be done for the W monoblocks due to a lack of diagnostics. However, the W monoblock edges clearly show traces of damage (melting, cracks) when exposed to the parallel heat flux due to relative misalignment of ITER-like PFUs during assembly. Optical hot spots were also evidenced, confirming the numerical simulations, although their impact on the operation and the lifetime of the components was limited.
Published: 2023
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13. Wall conditioning effects and boron migration during boron powder injection in ASDEX Upgrade

Author: K. Krieger, M. Balden, A. Bortolon, R. Dux, M. Griener, K. Hegele, F. Laggner, V. Rohde, and W.R. Wampler
Subjects: Nuclear fusion, Plasma physics, Wall conditioning, Boronisation, Nuclear engineering. Atomic power, TK9001-9401
Abstract: The efficacy of boron powder injection as a wall conditioning tool method in terms of its ability to create a sufficiently uniform boron layer on plasma-facing surfaces has been studied in ASDEX Upgrade. Boron powder was injected in two series of dedicated plasma discharges at varied injection rates and total amount injected. The resulting boron deposition was determined quantitatively by exposure of witness samples followed by ex-situ surface analysis of the retrieved samples. In both experiments, isotopically enriched boron was used to distinguish the deposition of the newly injected material from the residual boron fraction in the machine originating from previous glow discharge boronisations. It could be confirmed that the injected boron is migrating and re-deposited across plasma-facing wall surfaces already within one discharge. At erosion dominated divertor areas, the boron influx from the main chamber results in formation of a mixed tungsten–boron surface layer with a boron area density of O(1nm) whereas at deposition dominated areas closed boron layers grow with ongoing boron injection to a thickness of up to O(1μm). Extrapolating the radial boron deposition profile on the samples exposed in the main chamber to the limiter front yields a similar boron coverage of O(1μm), which is about ten times higher than typical values for glow discharge boronisation. Together with the observed reduction of oxygen level and improved wall pumping, the surface analysis results demonstrate that boron powder injection provides a suitable means to refresh the wall conditioning effect of a preceding glow discharge boronisation.
Published: 2023
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14. Surface features of strongly heated bulk tungsten divertor plates at ASDEX Upgrade

Author: V. Rohde, M. Balden, K. Hunger, I. Zammuto, A. Herrmann, and R. Neu
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Solid tungsten tiles exposed at the outer strike point module of the ASDEX Upgrade divertor show cracks parallel to surface in the bulk and humps at the surface. At ASDEX Upgrade these horizontal cracks were observed for the first time. About 10 % of all tiles exhibit protrusions originated by horizontal cracks about 3–5 mm below the surface. The position of this damage coincidence with the location of highest deposited energy, which varies for the different tiles due to the mounting. The tungsten at the locations of the horizontal cracks exhibits recrystallization and grain growth, presumably due to the worse thermal contact caused by the horizontal cracks. Although, the operation of AUG was not hampered by these damages, these tiles had to be exchanged preventing progression of these damages. High thermal stress due to temperature gradients is discussed to originate these cracks. Additionally, humps are found at the surface at the position of high heat flux. Their occurrence seems to be related to the increased number of high power discharges. Focused ion beam prepared cross sections indicate pores and cavities in and below these humps. This finding is discussed in the view of He bubble formation in tungsten.
Published: 2023
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15. Experiments and modelling on ASDEX Upgrade and WEST in support of tool development for tokamak reactor armour melting assessments

Author: S. Ratynskaia, K. Paschalidis, P. Tolias, K. Krieger, Y. Corre, M. Balden, M. Faitsch, A. Grosjean, Q. Tichit, and R.A. Pitts
Subjects: Tungsten melting, Melt motion, Thermionic emission, MEMENTO code, MEMOS-U model, Active cooling, Nuclear engineering. Atomic power, TK9001-9401
Abstract: The risk of metallic armour melting constitutes a major concern for ITER and DEMO. Combined computational and experimental effort has led to a successful understanding of melt dynamics in present-day tokamaks, but there remain unexplored melting regimes of relevance to future reactors. Analysis of recent poor-versus-efficient thermionic emitter sample exposures in ASDEX-Upgrade and ITER-like actively cooled tungsten leading edge exposures in WEST is presented. The coupled thermal response and melt dynamics is modelled with the new MEMENTO code employing the MEMOS-U physics model which has no adjustable parameters. In the weak Lorentz force regime accessed in the exposures, very close agreement between modelling and experiments is achieved not only for the deformation profiles, but also for the additional, unique to these experiments, constraints; simultaneous thermal response of two different materials in ASDEX-Upgrade and in-situ detection of melt build-up in WEST.
Published: 2022
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16. Influence of surface morphology on erosion of plasma-facing components in H-mode plasmas of ASDEX Upgrade

Author: A. Lahtinen, A. Hakola, J. Likonen, M. Balden, K. Krieger, S. Gouasmia, I. Bogdanovic Radovic, G. Provatas, M. Kelemen, S. Markelj, M. Pedroni, A. Uccello, E. Vassallo, D. Dellasega, and M. Passoni
Subjects: Erosion, Material migration, ASDEX Upgrade, H-mode, Marker samples, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Net erosion of plasma-facing materials was investigated at the low-field-side (outer) strike-point area of the ASDEX Upgrade (AUG) divertor during H-mode discharges with small and frequent ELMs. To this end, Au and Mo marker samples with different surface morphologies and geometries were exposed to plasmas using the DIM-II divertor manipulator. The results were compared to existing erosion and deposition patterns from various L- and H-mode experiments, in the latter case the main difference was the size and frequency of the ELMs.We noticed that increasing surface roughness reduces net erosion but less than what is the case in L-mode. On the other hand, net-erosion rates in H-mode are generally 2–5 times higher than the corresponding L-mode values, in addition to which exposure in H-mode conditions results in strong local variations in the poloidal and toroidal erosion/deposition profiles. The latter observation we associate with the large migration length, on the order of several cm, of the eroded material, resulting in strong competition between erosion and re-deposition processes especially at poloidal distances > 50 mm from the strike point. Considerable net erosion was measured throughout the analysed poloidal region unlike in L-mode where the main erosion peak occurs in the vicinity of the strike point. We attribute this qualitative difference to the slow decay lengths of the plasma flux and electron temperature in the applied H-mode scenario.Both erosion and deposition require detailed analyses at the microscopic scale and the deposition patterns may be drastically different for heavy and light impurities. Generally, the rougher the surface the more material will accumulate on locally shadowed regions behind protruding surface features. However, rough surfaces also exhibit more non-uniformities in the quality or even integrity of marker coatings produced on them, thus complicating the analyses of the experimental data.We conclude that local plasma parameters have a huge impact on the PFC erosion rates and, besides incident plasma flux, surface morphology and its temporal evolution have to be taken into account for quantitative estimates of erosion rates and PFC lifetime under reactor-relevant conditions.
Published: 2022
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17. Comparison experiment on the sputtering of EUROFER, RUSFER and CLAM steels by deuterium ions

Author: R. Arredondo, M. Balden, T. Schwarz-Selinger, T. Höschen, T. Dürbeck, K. Hunger, K. Schlueter, A. Golubeva, P. Wang, D. Terentyev, and W. Jacob
Subjects: Sputtering, RAFM, EUROFER, RUSFER, CLAM, Roughness, Nuclear engineering. Atomic power, TK9001-9401
Abstract: In this work, the RAFM steels EUROFER, RUSFER and CLAM, along with a reference pure Fe sample, were all exposed to the same source of deuterium and analyzed using the same techniques, allowing a direct comparison of the experimental results. A 200 eV/D mass-selected deuterium ion beam at the SIESTA facility was used to bombard the samples to a fluence of 5 × 1024 D m−2 at 450 K. The surface morphology of the samples was investigated with Scanning Electron Microscopy. The sputter yield of the samples was determined by weight-loss measurements and confirmed by measurements of the eroded depth. The near-surface enrichment of W and Ta was investigated via Energy-dispersive X-ray spectroscopy, X-ray Photoelectron Spectroscopy and Rutherford Backscattering Spectrometry. Grain-orientation-dependent sputtering was studied with Confocal Laser Scanning Microscopy and Electron Backscatter Diffraction. Lastly, Nuclear Reaction Analysis and Thermal Desorption Spectrometry were employed to analyze deuterium retention in all the samples. The erosion behavior of all three steels under deuterium bombardment was confirmed to be similar. The measured sputter yield was comparable for all three steels, and significantly lower than that of pure Fe. Likewise, all steels develop a needle-like surface morphology under the given exposure conditions and a W- and Ta-enriched layer in the range of few nanometers, while the Fe sample remained smooth. Retained deuterium amounts were also comparable among the steel samples, and were overall larger than the retention measured for the pure Fe sample.
Published: 2022
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18. Investigation of ELM-related Larmor ion flux into toroidal gaps of divertor target plates

Author: K. Krieger, M. Balden, M. Barac, I. Bogdanović Radović, D. Brida, M. Faitsch, J.P. Gunn, S. Markelj, M. Kelemen, A. Manhard, P. de Marne, R.A. Pitts, V. Rohde, the ASDEX Upgrade Team, and the EUROfusion MST1 Team
Subjects: nuclear fusion, plasma physics, ITER, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: A detailed assessment of the thermo-mechanical limits of the International Tokamak Experimental Reactor (ITER) divertor with respect to potential excessive local transient heat loads due to edge localised modes (ELMs) has revealed a particular power loading scenario arising from the fact that ELM ions expelled from the upstream pedestal region will arrive at the divertor target plates without substantial thermalisation. As a consequence of their Larmor gyration around magnetic field lines, they are able to penetrate toroidal gaps between individual monoblocks of the target plate structure and can deliver rather intense heat loads to monoblock side faces near the gap entrance. To verify that this ELM-induced loading, predicted by both ion orbit simulations and particle in cell simulations, really does occur, two dedicated experiments have been performed on the ASDEX Upgrade tokamak. In both experiments a model toroidal gap structure of similar dimensions to those of the ITER divertor target monoblocks was exposed to a series of identical H-mode discharges with strong type-I ELMs. The effects arising from the gyro motion of hot ELM ions were identified by inverting, in the second experiment, the directions of both toroidal field and plasma current, thus reversing the ion gyration direction. The local distribution of incident ion flux on the gap side faces was quantified by pre- and post-exposure analysis of platinum marker layers to determine quantitatively the erosion rate of the platinum marker. The results fully confirm the ion orbit code predictions with respect to the penetration depth of incident ions with gyro orbits of similar or larger radius than the gap width. Moreover, the results confirm that ELM ions do indeed arrive at the divertor with their typical pedestal energies and also allow conclusions to be drawn regarding the corresponding intra-ELM ion particle and power flux, which is not easy to quantify using Langmuir probes.
Published: 2023
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19. Arc behaviour on different materials in ASDEX Upgrade

Author: V. Rohde, M. Balden, and R. Neu
Subjects: Tokamak, ASDEX upgrade, Arcing, Plasma wall interaction, Dust, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Arcs, a source of dust particles and a localized erosion mechanism of the plasma-facing components, are found in all major fusion plasma devices. Measurements of arcs require diagnostics with high temporal and local resolution, which are not available at arc dominated locations in ASDEX Upgrade (AUG). To understand the erosion by arcing and to allow extrapolation for future fusion devices different materials are used to scan the material properties. In AUG, inserts were installed at the inner baffle region to measure the erosion by arcing. The use of polished inserts allows an accurate determination of the arc traces by depth maps obtained by laser profilometery. It turned out that the melting temperature of the materials is the main parameter for erosion. For tungsten mounted at the inner baffle, a region which is deposition dominated, an erosion rate by arcing of 1.2·1013 at cm−2 s−1 is measured. For Beryllium, 9.5·1013 at cm−2 s−1 is extrapolated from its thermal properties. As martensitic–ferritic low-activation steel is under discussion for the use in DEMO, magnetic steels were also investigated. Comparing stainless steel with magnetic steel, much deeper and wider craters are found in the latter one: they reach a depth of −80 μm. The erosion of magnetic steel by arcs is 40 times higher compared to stainless steel, which has almost the same physical properties.
Published: 2021
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20. Deuterium retention in tungsten fiber-reinforced tungsten composites

Author: A. Kärcher, J. Riesch, P. Almanstötter, A. Manhard, M. Balden, J.W. Coenen, K. Hunger, H. Maier, L. Raumann, D. Schwalenberg, and R. Neu
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: In future fusion reactors, plasma-facing materials (PFMs) have to withstand unique conditions such as high temperatures, ion and neutron irradiation. Tungsten (W) has been established as main candidate material due to its favorable properties regarding the fusion environment but brings one major challenge: Its brittleness at moderate temperatures can lead to failure of tungsten components. Tungsten fiber-reinforced tungsten (Wf/W), a tungsten matrix containing drawn tungsten fibers, was developed to mitigate this problem by using extrinsic toughening mechanisms to achieve pseudo-ductility. The deuterium (D) retention in Wf/W manufactured by chemical vapor deposition (CVD) has been investigated using Wf/W single layered model systems consisting of a single plane of unidirectional tungsten fibers embedded in a tungsten matrix produced by CVD. Various parameters with potential influence on the D retention, such as the choice of an erbium oxide interface and potassium doping, have been included in the investigation. The samples have been ground to varying distances between surface and fiber plane - exposing distinct details of the Wf/W microstructures at the surface. The samples were exposed to a low temperature D plasma at 370 K for 72 h resulting in a total fluence of 1025 D/m2. The D retention of all samples was measured by nuclear reaction analysis (NRA) and thermal desorption spectroscopy (TDS). The D retention in Wf/W composites is higher than in reference samples made from hot-rolled W by factors between 2 and 5. In addition, a comparison of NRA and TDS data indicates that D penetrates faster into the depth of Wf/W material than into hot-rolled tungsten.
Published: 2021
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21. Deuterium retention in tungsten based materials for fusion applications

Author: H. Maier, T. Schwarz-Selinger, R. Neu, C. Garcia-Rosales, M. Balden, A. Calvo, T. Dürbeck, A. Manhard, N. Ordás, and T.F. Silva
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: The tungsten “heavy alloy” HPM 1850, a liquid-phase sintered composite material with two weight percent Ni and one weight percent Fe, as well as the self-passivating tungsten alloy W-10Cr-0.5Y, a high temperature oxidation resistant alloy with 10 weight percent of Cr and 0.5 weight percent of Y, were investigated with respect to their deuterium retention. The samples were deuterium loaded in an electron cyclotron resonance plasma up to a fluence of 1025m−2. The deuterium retention was then investigated by Nuclear Reaction Analysis and by Thermal Desorption. In HPM 1850 the observed deuterium amount was similar to pure tungsten, however the outgassing behaviour during thermal desorption was considerably faster. In W-10Cr-0.5Y the released deuterium amount during thermal desorption was about one order of magnitude higher; by comparison of nuclear reaction analysis and thermal desorption this was attributed to deeper diffusion of deuterium into the bulk of the material. Keywords: Deuterium retention, Tungsten heavy alloy, Tungsten self-passivating alloy, Nuclear reaction analysis, Thermal desorption
Published: 2019
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22. MEMOS 3D modelling of ELM-induced transient melt damage on an inclined tungsten surface in the ASDEX Upgrade outer divertor

Author: E. Thorén, S. Ratynskaia, P. Tolias, R.A. Pitts, K. Krieger, M. Komm, and M. Balden
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: The first MEMOS 3D simulations of liquid metal motion on an inclined bulk tungsten sample transiently molten by edge-localized modes (ELMs) are reported. The exposures took place at the outer ASDEX-Upgrade divertor with the tungsten surface tangent intersecting the magnetic field at ∼ 18°. Simulations confirm that the observed poloidal melt motion is caused by the volumetric J × B force with J the bulk replacement current triggered by thermionic emission. The final erosion profile and total melt build up are reproduced by employing the escaping thermionic current dependence on the incident heat flux derived from dedicated particle-in-cell simulations. Modelling reveals that melt dynamics is governed by the volumetric Lorentz force, capillary flows due to thermal surface tension gradients and viscous deceleration. The effect of the evolving surface deformation, that locally alters the field-line inclination modifying the absorbed power flux and the escaping thermionic current, in the final surface morphology is demonstrated to be significant. Keywords: Melting, Tungsten, Divertor, Melt layer motion, MEMOS, Thermionic emission
Published: 2018
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23. Tungsten surface enrichment in EUROFER and Fe-W model systems studied by high-resolution time-of-flight rutherford backscattering spectroscopy

Author: M. Mayer, T.F. Silva, R. Arredondo, M. Balden, I. Bogdanović-Radović, T. Höschen, H. Maier, M. Oberkofler, L. Ru, and Z. Siketić
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Time-of-flight Rutherford backscattering spectroscopy (ToF-RBS) with incident heavy ions offers a substantially improved depth resolution compared to conventional RBS with incident He ions. The new Garching ToF-RBS detector is located at a scattering angle of 150° with a free flight path of 1.313 m and a time resolution of 600 ps. The experimentally achieved depth resolution at the surface of W-containing Fe samples is 2–3 nm using incident Si ions. Model systems consisting of Fe layers with 0.7, 1.5 and 4.2 at% W and EUROFER steel (containing 0.34 at% W + Ta) were eroded by 200 eV D ions to a fluence of 1023 D/m2 at 310 K and 900 K. W depth profiles were measured using ToF-RBS, light impurities at the surface were detected using time-of-flight elastic recoil detection analysis (ToF-ERDA). The data sets from the two techniques were analyzed self-consistently. In all cases W enrichment at the surface was observed. The enrichment at 310 K is in good agreement with SDTrimSP simulations if the experimentally achieved depth resolution is taken into account. Annealing of the model systems with 0.7 and 1.5 at% W to 900 K for 10 h in vacuum resulted also in a W-enriched surface layer. Keywords: Rutherford Backscattering Spectroscopy, RBS, ToF-RBS, Tungsten surface enrichment, EUROFER, MultiSIMNRA
Published: 2018
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24. ERO modelling of net and gross erosion of marker samples exposed to L-mode plasmas on ASDEX Upgrade

Author: A. Hakola, A. Keitaanranta, H. Kumpulainen, A. Lahtinen, J. Likonen, M. Balden, M. Cavedon, K. Krieger, M. Airila, and M. Groth
Subjects: Erosion, Material migration, ASDEX Upgrade, L-mode, Marker samples, Nuclear engineering. Atomic power, TK9001-9401
Abstract: In this paper, we report experimental and numerical investigations of gross and net erosion of gold (Au) and molybdenum (Mo), proxies for the common plasma-facing material tungsten (W), during L-mode plasma discharges in deuterium (D) in the outer strike-point region of the ASDEX Upgrade tokamak. To this end, erosion profiles of different marker spots (for Au, dimensions 1 × 1 and 5 × 5 mm2) and marker coatings (for Mo) have been determined and modelled using the ERO code. The smaller marker spots were designed to quantify the gross-erosion rate while on the bigger markers local prompt re-deposition of Au allowed obtaining data on net erosion.The experimental results indicate relatively uniform erosion profiles across the marker spots or coatings, very little re-deposition elsewhere, and the largest erosion taking place close to the strike point. Compared to W, the markers show up to 15 times higher net erosion but no major differences in the poloidal migration lengths of Au and W can be seen. Gold thus appears to be a proper choice for studying migration of W in the divertor region.The ERO simulations with different background plasmas are able to reproduce the main features of the experimental net erosion profile of Au. Of the studied parameters, electron temperature has the strongest impact on erosion: doubling the temperature enhances erosion by a factor of 2.5–3. In contrast, for Mo, the simulated net erosion is ~ 3 times smaller than what experimental data indicate. The discrepancies can be attributed to the deviations of the background plasma profiles from the measured ones as well as to the applied models or approximations for the ion temperature, plasma potential, and sheath characteristics in ERO. In addition, the surrounding areas of the marker samples being covered with impurities and W from previous experiments may have considerably reduced the actual re-deposition of Mo.All the simulations predict a toroidal tail of re-deposited particles, downstream of the markers, but the particle density seems to be below the experimental detection threshold. The comparison between the 1 × 1 mm2 and 5 × 5 mm2 marker spots further reveal that re-deposition drops from >50% to
Published: 2020
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25. Impact of surface enrichment and morphology on sputtering of EUROFER by deuterium

Author: R. Arredondo, M. Balden, A. Mutzke, U. von Toussaint, S. Elgeti, T. Höschen, K. Schlueter, M. Mayer, M. Oberkofler, and W. Jacob
Subjects: Sputtering, EUROFER, RAFM, SDTrimSP, Roughness, SDTrimSP-3D, SEM, Nuclear engineering. Atomic power, TK9001-9401
Abstract: EUROFER is a Reduced Activation Ferritic Martensitic (RAFM) steel developed as structural material for future fusion power plants and is considered as first-wall material in recessed areas of DEMO. Recent work has shown a fluence-dependent decrease of the sputter yield for bombardment with deuterium ions in the energy range of 100 to about 500 eV. This decrease was previously attributed to preferential sputtering of the lower mass constituents in EUROFER, such as Fe and Cr, compared to the higher mass alloying elements. This leads to an increase of the surface tungsten concentration. However, it was also observed that, after sputtering, the samples had developed a very rough surface morphology. In this work, the combined influence of surface roughness and W surface enrichment on the sputter yield of EUROFER under bombardment with 200 eV deuterium ions was studied. The influence of surface roughness was determined with the aid of Scanning Electron Microscopy (SEM) and SDTrimSP-3D simulations. W surface enrichment was investigated applying sputter X-Ray Photoelectron Spectroscopy (XPS) depth-profiling and Rutherford backscattering spectrometry (RBS). After bombardment to a fluence of 1024 D m−2 (at 200 eV per deuterium) a reduction of the sputter yield to 29% ± 5% of the initial value was measured by weight-loss measurements. This reduction is in good agreement with published values. Two distinct surface morphologies, consisting of smooth and spiked surfaces, were observed on the EUROFER sample after sputtering. Based on the experimental results, the combined effect of the two factors, surface roughness and W surface enrichment, is estimated to be responsible for a reduction in the sputter yield to 27% ± 4% of the initial value, which is in excellent agreement with the measured value. Our assessment shows that both surface morphology and W surface enrichment contribute significantly to the reduction of the sputter yield of EUROFER under the given experimental conditions, and are sufficient to fully explain the experimentally observed reduction in the sputter yield.
Published: 2020
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26. Erosion of EUROFER steel by mass-selected deuterium ion bombardment

Author: K. Sugiyama, M. Balden, S. Elgeti, T. Höschen, M. Oberkofler, J. Roth, and W. Jacob
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: The erosion behaviour of EUROFER steel due to mono-energetic deuterium (D) ion bombardment in the energy range of 100–1000 eV/D was investigated. At low fluences, the sputtering yield is comparable to that of pure iron (Fe). It then decreases with increasing fluence and tends toward a steady state at larger fluences. The largest experimentally investigated fluences are of the order of several 1024 D/m2. The yield reduction is more pronounced for lower D impinging energies. A simple model is presented within which the evolution of the yield can be described by an exponential decay, using empirical values for the fitting parameters. In this model, the yield reduction is caused by preferential sputtering of Fe and the consequent development of a tungsten- (W-) enriched surface layer. SDTrimSP simulations also confirm the appearance of a W-enriched surface layer. However, the experimentally observed fluence dependence of the sputtering yield could not satisfactorily be reproduced in these simulations. The resulting enrichment layer thicknesses below 1 Å stretch the physics model implemented in SDTrimSP beyond its validity range. Experimentally, surface enrichment of W was qualitatively confirmed in Rutherford backscattering and sputter X-ray photoelectron spectroscopy measurements. However, the measured depth profiles are very likely influenced by the observed surface roughening caused by the D irradiation. Electron microscopy revealed the inhomogeneous W distribution on the un-irradiated sample as well as a grain-dependence of erosion and grain-dependent topography development. The inclusion of surface topography in the description of the erosion could be the key to improve the agreement between model predictions and the experiment. Keywords: RAFM steel, Erosion, Plasma-material interactions
Published: 2018
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27. Surface modification and sputtering erosion of iron and copper exposed to low-energy, high-flux deuterium plasmas seeded with metal species

Author: V.Kh. Alimov, Y. Hatano, M. Balden, M. Oyaizu, K. Isobe, H. Nakamura, and T. Hayashi
Subjects: Deuterium plasma, Iron, Copper, Tungsten, Surface morphology, Sputtering erosion, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Four sets of targets were used in this study: (1) Fe targets surrounded with 304 type stainless steel composed of mid-Z elements: Fe, Cr, Ni, and Mn (designated as Fe[304SS] targets), (2) Fe targets surrounded with high-Z tungsten (designated as Fe[W] targets), (3) Cu targets surrounded with mid-Z copper (designated as Cu[Cu] targets), and (4) Cu targets surrounded with high-Z tungsten (designated as Cu[W] targets). The targets were exposed to low-energy (140 and 200eV), high-flux (about 1022 D/m2s) deuterium (D) plasmas at various temperatures in the range from 355 to 740K. The surface morphology of the Fe and Cu targets is found to be dependent strongly on atomic number of re-deposited species and on the exposure temperature. For the Fe[W] and Cu[W] targets, due to formation of the W-enriched nano-sized structures on the target surfaces, the sputtering erosion yield is lower than that for the Fe[304SS] and Cu[Cu] targets, respectively. For the Fe[304SS], Fe[W], and Cu[W] targets, the sputtering erosion yield is increased distinctly as the exposure temperature rises from 355 to 740K.
Published: 2017
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28. Microstructural stability of spark-plasma-sintered Wf/W composite with zirconia interface coating under high-heat-flux hydrogen beam irradiation

Author: M. Avello de Lama, M. Balden, H. Greuner, T. Höschen, J. Matejicek, and J.H. You
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Tungsten is considered as the most suitable material for the plasma-facing armour of future fusion reactors. However, in spite of many advantageous properties, pure tungsten has a major drawback, namely, brittleness at lower temperatures and embrittlement by neutron irradiation. Tungsten fibre-reinforced tungsten (Wf/W) composites are thought to be a promising candidate material for armour owing to the pseudo-toughness effect which is based on controlled cracking of coated interfaces. In this material concept, the reliability of the material during service relies on the fabrication quality as well as the stability of microstructure, particularly, of the interfacial coating under high-heat-flux loads. In this paper, the durability and chemical stability of Wf/W composite specimens under cyclic heat-flux loads up to 20 MW/m² (surface temperature: 1260 °C) was investigated using hydrogen neutral beam. The bulk material was fabricated by means of spark-plasma-sintering (SPS) method using fine tungsten powder and a stack of tungsten wire meshes as reinforcement where the surface of the wire was coated with zirconia thin film to produce an engineered interface. The impact of plasma beam irradiation on microstructure was examined for two kinds of specimens produced at different sintering temperatures, 1400 °C and 1700 °C. Results of microscopic (SEM) and chemical (EDX) analysis are presented comparing the microstructure and element distribution maps obtained before and after heat flux loading. Effects of different sintering temperatures on damage behaviour are discussed. The present composite materials are shown to be applicable as plasma-facing material for high-heat-flux components.
Published: 2017
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29. Reprint of: Arc erosion of full metal plasma facing components at the inner baffle region of ASDEX Upgrade

Author: V. Rohde and M. Balden
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: At the inner baffle of the AUG divertor massive polished inserts of tungsten and P92 steel were installed to measure the erosion by arcing. For tungsten most of the traces are less than 0.4µm deep and a similar amount of tungsten is deposited close to the traces. Few craters up to 4µm resulting in an average erosion rate of 2×1013 at cm−2s−1 are observed. The behaviour for P92 steel is quite different: most of the traces are 4µm deep, up to 80µm were observed. An average erosion rate of 400×1013 at cm−2s−1, i.e. more than a factor of hundred higher compared to tungsten, is found. Therefore, erosion by arcing has to be taken into account to determine the optimal material mix for future fusion devices.
Published: 2017
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30. Microstructure and defect analysis in the vicinity of blisters in polycrystalline tungsten

Author: A. Manhard, U. von Toussaint, M. Balden, S. Elgeti, T. Schwarz-Selinger, L. Gao, S. Kapser, T. Płociński, J. Grzonka, M. Gloc, and Ł. Ciupiński
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Up to now, analyzing the production of dislocation-type defects in the subsurface region of plasma or ion-exposed tungsten samples has been hampered by the challenging production of suitable cross-section samples for transmission electron microscopy. We present two reliable methods based on precision electropolishing to prepare cross-sections of tungsten that allow direct imaging of dislocation-type defects by scanning as well as by transmission electron microscopy. Using these methods, we are able to demonstrate a clear enhancement of the dislocation density in the caps of blisters on tungsten exposed to H isotope plasma, i.e., of surface morphologies that are correlated to subsurface cavities. As a benchmark, we also show a cross-section of tungsten irradiated by 20 MeV W6+ ions. Keywords: Tungsten, Plasma, Blistering, Cross-section, Electropolishing, Dislocations
Published: 2017
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31. Experiences with a solid tungsten divertor in ASDEX Upgrade

Author: A. Herrmann, I. Zammuto, M. Balden, H. Greuner, N. Jaksic, A. Kallenbach, M. Li, R. Neu, and V. Rohde
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: In 2013 a redesigned solid tungsten divertor, Div-III, was installed in ASDEX Upgrade. In two experimental campaigns more than 2700 plasma discharges with up to 10s duration, 110MJ plasma heating, and reaching a Psep/R of 10MW/m were conducted. Div-III is an adiabatically loaded divertor with tungsten target tiles clamped onto a water cooled structure. The tungsten target tiles were inspected and characterized during the shut-down period in 2014. As a result of the target inspection characteristic modifications of the plasma exposed tiles were detected that were not found during the target qualification in a high heat load test facility. 126 out of 128 tiles reveal deep cracks through the target. A lot of tiles show shallow cracks in the high heat load region and finally protruding tiles with strong local damages were found. It should be noted that none of these target damages have caused an unscheduled opening of ASDEX Upgrade. Keywords: Solid tungsten, Divertor, ASDEX Upgrade, Plasma energy
Published: 2017
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32. Effect of the surface temperature on surface morphology, deuterium retention and erosion of EUROFER steel exposed to low-energy, high-flux deuterium plasma

Author: M. Balden, S. Elgeti, M. Zibrov, K. Bystrov, and T.W. Morgan
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Samples of EUFROFER, a reduced activation ferritic martensitic steel, were exposed in the linear plasma device Pilot-PSI to a deuterium (D) plasma with incident ion energy of ∼40eV and incident D flux of 2–6×1023D/m2s to fluences up to 1027D/m2 at surface temperatures ranging from 400K to 950K. The main focus of the study lays on the surface morphology changes dependent on the surface temperature and the surface composition evolution, e.g., the enrichment in tungsten; but also the erosion and the D retention are studied. The created surface morphology varies strongly with surface temperature from needle-like to corral-like structures. The visible lateral length scale of the formed structures is in the range of tens of nanometres to above 1µm and exhibits two thermal activated regimes below and above ∼770K with activation energies of 0.2eV and 1.3eV, respectively. The lateral variation of the enrichment of heavy elements on the surface is correlated to this surface morphology at least in the high temperature regime, independent of the origin of the enrichment (intrinsic from the sample or deposited by the plasma). Also the erosion exhibits temperature dependence at least above ∼770K as well as a fluence dependence. The amount of deuterium retained in the top 500nm is almost independent of the exposure temperature and is of the order of 1018D/m2, which would correspond to a sub-monolayer D coverage on the surface. The retained D in the volume summing up over the complete samples exceeds the D retained close to the surface by one order of magnitude. Keywords: Plasma facing material, Surface morphology, Erosion, Steel, Plasma exposure
Published: 2017
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33. Surface modification of He pre-exposed tungsten samples by He plasma impact in the divertor manipulator of ASDEX Upgrade

Author: S. Brezinsek, A. Hakola, H. Greuner, M. Balden, A. Kallenbach, M. Oberkofler, G. De Temmerman, D. Douai, A. Lahtinen, B. Böswirth, D. Brida, R. Caniello, D. Carralero, S. Elgeti, K. Krieger, H. Mayer, G. Meisl, S. Potzel, V. Rohde, B. Sieglin, A. Terra, R. Neu, and Ch. Linsmeier
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Tungsten (W) will be used as material for plasma-facing components (PFCs) in the divertor of ITER and interact with Helium (He) ions either from initial He plasma operation or from Deuterium-Tritium (DT) fusion reactions in the active operation phase. Laboratory experiments reported that in a specific operational window of impact energy, ion fluence, and surface temperature (Ein ≥ 20 eV, ϕ ≥ 1 × 1024 He+mBt=2.5T,Ip=0.8MA,Paux≃8.0MW Tsurf ≥ 1000 K) a modification of W surfaces occurs resulting in the formation of He-induced W nanostructures. Experiments in ASDEX Upgrade H-mode plasmas (Ein=37keV T, ϕ≃0.75×1024He0m−2 MA, Paux ≃ 8.0 MW) in He have been carried out to investigate in detail (a) the potential growth of W nanostructures on pre-damaged W samples incorporating He nanobubbles, and (b) the potential ELM-induced erosion of W nanostructure. Both W surface modifications were generated artificially in the GLADIS facility by He bombardment of W samples at ϕ≃1×1024He0m−2 keV (a) to ϕ ≃ 0.75 × 1024 He0mϕ≃1.6×1024He+m−2 at Tsurf ≃ 1800 K and (b) ϕ ≃ 1 × 1024 He0m−2 at Tsurf ≃ 2300 K prior to exposure in the divertor manipulator of ASDEX Upgrade. Though in part (a) conditions of W nanostructure growth with a total He ion fluence of ϕ ≃ 1.6 × 1024 He+m−2 and peak He ion impact energies above 150 eV were met, no growth could be detected. In part (b) lower density plasmas with more pronounced type I ELMs, carrying energetic He ions in the keV range, were executed with the strike-line positioned on 2 µm thick W nanostructure accumulating a fluence of ϕ ≃ 0.8 × 1024 He+m−2. Post-mortem analysis revealed that co-deposition by predominantly W, and Boron (B), eroded at the main chamber wall and transported into the divertor, took place on all W samples. Erosion of W nanostructure or its formation was hindered by the fact that the outer divertor at the location of the samples was turned under these He plasma conditions into a net deposition zone by W, B and Carbon (C) ions. The surface morphology with large roughness and effective surface area act as a catcher for the impinging impurities. Thus, apart from operation in the existence diagram of W nanostructure with respect to Tsurf, ϕ, and Ein, also the impinging impurity flux contribution needs to be considered in predictions concerning the formation of W nanostructures. Keywords: PSI, ASDEX Upgrade, ITER, W divertor, W nanostructure, Helium
Published: 2017
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34. Tungsten fibre-reinforced composites for advanced plasma facing components

Author: R. Neu, J. Riesch, A.v. Müller, M. Balden, J.W. Coenen, H. Gietl, T. Höschen, M. Li, S. Wurster, and J.-H. You
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: The European Fusion Roadmap foresees water cooled plasma facing components in a first DEMO design in order to provide enough margin for the cooling capacity and to only moderately extrapolate the technology which was developed and tested for ITER. In order to make best use of the water cooling concept copper (Cu) and copper-chromium-zirconium alloy (CuCrZr) are envisaged as heat sink whereas as armour tungsten (W) based materials will be used. Combining both materials in a high heat flux component asks for an increase of their operational range towards higher temperature in case of Cu/CuCrZr and lower temperatures for W. A remedy for both issues- brittleness of W and degrading strength of CuCrZr- could be the use of W fibres (Wf) in W and Cu based composites. Fibre preforms could be manufactured with industrially viable textile techniques. Flat textiles with a combination of 150/70 µm W wires have been chosen for layered deposition of tungsten-fibre reinforced tungsten (Wf/W) samples and tubular multi-layered braidings with W wire thickness of 50 µm were produced as a preform for tungsten-fibre reinforced copper (Wf /Cu) tubes. Cu melt infiltration was performed together with an industrial partner resulting in sample tubes without any blowholes. Property estimation by mean field homogenisation predicts strongly enhanced strength of the Wf/CuCrZr composite compared to its pure CuCrZr counterpart. Wf /W composites show very high toughness and damage tolerance even at room temperature. Cyclic load tests reveal that the extrinsic toughening mechanisms counteracting the crack growth are active and stable. FEM simulations of the Wf/W composite suggest that the influence of fibre debonding, which is an integral part of the toughening mechanisms, and reduced thermal conductivity of the fibre due to the necessary interlayers do not strongly influence the thermal properties of future components. Keywords: Plasma facing components, Tungsten, Copper, Composite materials, (Extrinsic) toughening
Published: 2017
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35. Arc erosion of full metal plasma facing components at the inner baffle region of ASDEX Upgrade

Author: V. Rohde and M. Balden
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: At the inner baffle of the AUG divertor massive polished inserts of tungsten and P92 steel were installed to measure the erosion by arcing. For tungsten most of the traces are less than 0.4µm deep and a similar amount of tungsten is deposited close to the traces. Few craters up to 4µm resulting in an average erosion rate of 2×1013 at cm−2s−1 are observed. The behaviour for P92 steel is quite different: most of the traces are 4µm deep, up to 80µm were observed. An average erosion rate of 400×1013 at cm−2s−1, i.e. more than a factor of hundred higher compared to tungsten, is found. Therefore, erosion by arcing has to be taken into account to determine the optimal material mix for future fusion devices.
Published: 2016
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36. Global scaling of the heat transport in fusion plasmas

Author: Sara Moradi, Johan Anderson, Michele Romanelli, Hyun-Tae Kim, JET contributors, X. Litaudon, S. Abduallev, M. Abhangi, P. Abreu, M. Afzal, K. M. Aggarwal, T. Ahlgren, J. H. Ahn, L. Aho-Mantila, N. Aiba, M. Airila, R. Albanese, V. Aldred, D. Alegre, E. Alessi, P. Aleynikov, A. Alfier, A. Alkseev, M. Allinson, B. Alper, E. Alves, G. Ambrosino, R. Ambrosino, L. Amicucci, V. Amosov, E. Andersson Sundén, M. Angelone, M. Anghel, C. Angioni, L. Appel, C. Appelbee, P. Arena, M. Ariola, H. Arnichand, S. Arshad, A. Ash, N. Ashikawa, V. Aslanyan, O. Asunta, F. Auriemma, Y. Austin, L. Avotina, M. D. Axton, C. Ayres, M. Bacharis, A. Baciero, D. Baião, S. Bailey, A. Baker, I. Balboa, M. Balden, N. Balshaw, R. Bament, J. W. Banks, Y. F. Baranov, M. A. Barnard, D. Barnes, M. Barnes, R. Barnsley, A. Baron Wiechec, L. Barrera Orte, M. Baruzzo, V. Basiuk, M. Bassan, R. Bastow, A. Batista, P. Batistoni, R. Baughan, B. Bauvir, L. Baylor, B. Bazylev, J. Beal, P. S. Beaumont, M. Beckers, B. Beckett, A. Becoulet, N. Bekris, M. Beldishevski, K. Bell, F. Belli, M. Bellinger, É. Belonohy, N. Ben Ayed, N. A. Benterman, H. Bergsȧker, J. Bernardo, M. Bernert, M. Berry, L. Bertalot, C. Besliu, M. Beurskens, B. Bieg, J. Bielecki, T. Biewer, M. Bigi, P. Bìlkovà, F. Binda, A. Bisoffi, J. P. S. Bizarro, C. Björkas, J. Blackburn, K. Blackman, T. R. Blackman, P. Blanchard, P. Blatchford, V. Bobkov, A. Boboc, G. Bodnàr, O. Bogar, I. Bolshakova, T. Bolzonella, N. Bonanomi, F. Bonelli, J. Boom, J. Booth, D. Borba, D. Borodin, I. Borodkina, A. Botrugno, C. Bottereau, P. Boulting, C. Bourdelle, M. Bowden, C. Bower, C. Bowman, T. Boyce, C. Boyd, H. J. Boyer, J. M. A. Bradshaw, V. Braic, R. Bravanec, B. Breizman, S. Bremond, P. D. Brennan, S. Breton, A. Brett, S. Brezinsek, M. D. J. Bright, M. Brix, W. Broeckx, M. Brombin, A. Brosawski, D. P. D. Brown, M. Brown, E. Bruno, J. Bucalossi, J. Buch, J. Buchanan, M. A. Buckley, R. Budny, H. Bufferand, M. Bulman, N. Bulmer, P. Bunting, P. Buratti, A. Burckhart, A. Buscarino, A. Busse, N. K. Butler, I. Bykov, J. Byrne, P. Cahyna, G. Calabrò, I. Calvo, Y. Camenen, P. Camp, D. C. Campling, J. Cane, B. Cannas, A. J. Capel, P. J. Card, A. Cardinali, P. Carman, M. Carr, D. Carralero, L. Carraro, B. B. Carvalho, I. Carvalho, P. Carvalho, F. J. Casson, C. Castaldo, N. Catarino, J. Caumont, F. Causa, R. Cavazzana, K. Cave-Ayland, M. Cavinato, M. Cecconello, S. Ceccuzzi, E. Cecil, A. Cenedese, R. Cesario, C. D. Challis, M. Chandler, D. Chandra, C. S. Chang, A. Chankin, I. T. Chapman, S. C. Chapman, M. Chernyshova, G. Chitarin, G. Ciraolo, D. Ciric, J. Citrin, F. Clairet, E. Clark, M. Clark, R. Clarkson, D. Clatworthy, C. Clements, M. Cleverly, J. P. Coad, P. A. Coates, A. Cobalt, V. Coccorese, V. Cocilovo, S. Coda, R. Coelho, J. W. Coenen, I. Coffey, L. Colas, S. Collins, D. Conka, S. Conroy, N. Conway, D. Coombs, D. Cooper, S. R. Cooper, C. Corradino, Y. Corre, G. Corrigan, S. Cortes, D. Coster, A. S. Couchman, M. P. Cox, T. Craciunescu, S. Cramp, R. Craven, F. Crisanti, G. Croci, D. Croft, K. Crombé, R. Crowe, N. Cruz, G. Cseh, A. Cufar, A. Cullen, M. Curuia, A. Czarnecka, H. Dabirikhah, P. Dalgliesh, S. Dalley, J. Dankowski, D. Darrow, O. Davies, W. Davis, C. Day, I. E. Day, M. De Bock, A. de Castro, E. de la Cal, E. de la Luna, G. De Masi, J. L. de Pablos, G. De Temmerman, G. De Tommasi, P. de Vries, K. Deakin, J. Deane, F. Degli Agostini, R. Dejarnac, E. Delabie, N. den Harder, R. O. Dendy, J. Denis, P. Denner, S. Devaux, P. Devynck, F. Di Maio, A. Di Siena, C. Di Troia, P. Dinca, R. Dinca, B. Ding, T. Dittmar, H. Doerk, R. P. Doerner, T. Donné, S. E. Dorling, S. Dormido-Canto, S. Doswon, D. Douai, P. T. Doyle, A. Drenik, P. Drewelow, P. Drews, Ph. Duckworth, R. Dumont, P. Dumortier, D. Dunai, M. Dunne, I. Duran, F. Durodié, P. Dutta, B. P. Duval, R. Dux, K. Dylst, N. Dzysiuk, P. V. Edappala, J. Edmond, A. M. Edwards, J. Edwards, Th. Eich, A. Ekedahl, R. El-Jorf, C. G. Elsmore, M. Enachescu, G. Ericsson, F. Eriksson, J. Eriksson, L. G. Eriksson, B. Esposito, S. Esquembri, H. G. Esser, D. Esteve, B. Evans, G. E. Evans, G. Evison, G. D. Ewart, D. Fagan, M. Faitsch, D. Falie, A. Fanni, A. Fasoli, J. M. Faustin, N. Fawlk, L. Fazendeiro, N. Fedorczak, R. C. Felton, K. Fenton, A. Fernades, H. Fernandes, J. Ferreira, J. A. Fessey, O. Février, O. Ficker, A. Field, S. Fietz, A. Figueiredo, J. Figueiredo, A. Fil, P. Finburg, M. Firdaouss, U. Fischer, L. Fittill, M. Fitzgerald, D. Flammini, J. Flanagan, C. Fleming, K. Flinders, N. Fonnesu, J. M. Fontdecaba, A. Formisano, L. Forsythe, L. Fortuna, E. Fortuna-Zalesna, M. Fortune, S. Foster, T. Franke, T. Franklin, M. Frasca, L. Frassinetti, M. Freisinger, R. Fresa, D. Frigione, V. Fuchs, D. Fuller, S. Futatani, J. Fyvie, K. Gàl, D. Galassi, K. Galazka, J. Galdon-Quiroga, J. Gallagher, D. Gallart, R. Galvão, X. Gao, Y. Gao, J. Garcia, A. Garcia-Carrasco, M. Garca-Munoz, J.-L. Gardarein, L. Garzotti, P. Gaudio, E. Gauthier, D. F. Gear, S. J. Gee, B. Geiger, M. Gelfusa, S. Gerasimov, G. Gervasini, M. Gethins, Z. Ghani, M. Ghate, M. Gherendi, J. C. Giacalone, L. Giacomelli, C. S. Gibson, T. Giegerich, C. Gil, L. Gil, S. Gilligan, D. Gin, E. Giovannozzi, J. B. Girardo, C. Giroud, G. Giruzzi, S. Glöggler, J. Godwin, J. Goff, P. Gohil, V. Goloborod'ko, R. Gomes, B. Goncalves, M. Goniche, M. Goodliffe, A. Goodyear, G. Gorini, M. Gosk, R. Goulding, A. Goussarov, R. Gowland, B. Graham, M. E. Graham, J. P. Graves, N. Grazier, P. Grazier, N. R. Green, H. Greuner, B. Grierson, F. S. Griph, C. Grisolia, D. Grist, M. Groth, R. Grove, C. N. Grundy, J. Grzonka, D. Guard, C. Guérard, C. Guillemaut, R. Guirlet, C. Gurl, H. H. Utoh, L. J. Hackett, S. Hacquin, A. Hagar, R. Hager, A. Hakola, M. Halitovs, S. J. Hall, S. P. Hallworth Cook, C. Hamlyn-Harris, K. Hammond, C. Harrington, J. Harrison, D. Harting, F. Hasenbeck, Y. Hatano, D. R. Hatch, T. D. V. Haupt, J. Hawes, N. C. Hawkes, J. Hawkins, P. Hawkins, P. W. Haydon, N. Hayter, S. Hazel, P. J. L. Heesterman, K. Heinola, C. Hellesen, T. Hellsten, W. Helou, O. N. Hemming, T. C. Hender, M. Henderson, S. S. Henderson, R. Henriques, D. Hepple, G. Hermon, P. Hertout, C. Hidalgo, E. G. Highcock, M. Hill, J. Hillairet, J. Hillesheim, D. Hillis, K. Hizanidis, A. Hjalmarsson, J. Hobirk, E. Hodille, C. H. A. Hogben, G. M. D. Hogeweij, A. Hollingsworth, S. Hollis, D. A. Homfray, J. Horàcek, G. Hornung, A. R. Horton, L. D. Horton, L. Horvath, S. P. Hotchin, M. R. Hough, P. J. Howarth, A. Hubbard, A. Huber, V. Huber, T. M. Huddleston, M. Hughes, G. T. A. Huijsmans, C. L. Hunter, P. Huynh, A. M. Hynes, D. Iglesias, N. Imazawa, F. Imbeaux, M. Imrìŝek, M. Incelli, P. Innocente, M. Irishkin, I. Ivanova-Stanik, S. Jachmich, A. S. Jacobsen, P. Jacquet, J. Jansons, A. Jardin, A. Järvinen, F. Jaulmes, S. Jednoróq, I. Jenkins, C. Jeong, I. Jepu, E. Joffrin, R. Johnson, T. Johnson, Jane Johnston, L. Joita, G. Jones, T. T. C. Jones, K. K. Hoshino, A. Kallenbach, K. Kamiya, J. Kaniewski, A. Kantor, A. Kappatou, J. Karhunen, D. Karkinsky, I. Karnowska, M. Kaufman, G. Kaveney, Y. Kazakov, V. Kazantzidis, D. L. Keeling, T. Keenan, J. Keep, M. Kempenaars, C. Kennedy, D. Kenny, J. Kent, O. N. Kent, E. Khilkevich, H. T. Kim, H. S. Kim, A. Kinch, C. King, D. King, R. F. King, D. J. Kinna, V. Kiptily, A. Kirk, K. Kirov, A. Kirschner, G. Kizane, C. Klepper, A. Klix, P. Knight, S. J. Knipe, S. Knott, T. Kobuchi, F. Köchl, G. Kocsis, I. Kodeli, L. Kogan, D. Kogut, S. Koivuranta, Y. Kominis, M. Köppen, B. Kos, T. Koskela, H. R. Koslowski, M. Koubiti, M. Kovari, E. Kowalska-Strzeciwilk, A. Krasilnikov, V. Krasilnikov, N. Krawczyk, M. Kresina, K. Krieger, A. Krivska, U. Kruezi, I. Ksiazek, A. Kukushkin, A. Kundu, T. Kurki-Suonio, S. Kwak, R. Kwiatkowski, O. J. Kwon, L. Laguardia, A. Lahtinen, A. Laing, N. Lam, H. T. Lambertz, C. Lane, P. T. Lang, S. Lanthaler, J. Lapins, A. Lasa, J. R. Last, E. Laszynska, R. Lawless, A. Lawson, K. D. Lawson, A. Lazaros, E. Lazzaro, J. Leddy, S. Lee, X. Lefebvre, H. J. Leggate, J. Lehmann, M. Lehnen, D. Leichtle, P. Leichuer, F. Leipold, I. Lengar, M. Lennholm, E. Lerche, A. Lescinskis, S. Lesnoj, E. Letellier, M. Leyland, W. Leysen, L. Li, Y. Liang, J. Likonen, J. Linke, Ch. Linsmeier, B. Lipschultz, G. Liu, Y. Liu, V. P. Lo Schiavo, T. Loarer, A. Loarte, R. C. Lobel, B. Lomanowski, P. J. Lomas, J. Lönnroth, J. M. López, J. López-Razola, R. Lorenzini, U. Losada, J. J. Lovell, A. B. Loving, C. Lowry, T. Luce, R. M. A. Lucock, A. Lukin, C. Luna, M. Lungaroni, C. P. Lungu, M. Lungu, A. Lunniss, I. Lupelli, A. Lyssoivan, N. Macdonald, P. Macheta, K. Maczewa, B. Magesh, P. Maget, C. Maggi, H. Maier, J. Mailloux, T. Makkonen, R. Makwana, A. Malaquias, A. Malizia, P. Manas, A. Manning, M. E. Manso, P. Mantica, M. Mantsinen, A. Manzanares, Ph. Maquet, Y. Marandet, N. Marcenko, C. Marchetto, O. Marchuk, M. Marinelli, M. Marinucci, T. Markovic, D. Marocco, L. Marot, C. A. Marren, R. Marshal, A. Martin, Y. Martin, A. Martín de Aguilera, F. J. Martínez, J. R. Martín-Solís, Y. Martynova, S. Maruyama, A. Masiello, M. Maslov, S. Matejcik, M. Mattei, G. F. Matthews, F. Maviglia, M. Mayer, M. L. Mayoral, T. May-Smith, D. Mazon, C. Mazzotta, R. McAdams, P. J. McCarthy, K. G. McClements, O. McCormack, P. A. McCullen, D. McDonald, S. McIntosh, R. McKean, J. McKehon, R. C. Meadows, A. Meakins, F. Medina, M. Medland, S. Medley, S. Meigh, A. G. Meigs, G. Meisl, S. Meitner, L. Meneses, S. Menmuir, K. Mergia, I. R. Merrigan, Ph. Mertens, S. Meshchaninov, A. Messiaen, H. Meyer, S. Mianowski, R. Michling, D. Middleton-Gear, J. Miettunen, F. Militello, E. Militello-Asp, G. Miloshevsky, F. Mink, S. Minucci, Y. Miyoshi, J. Mlynàr, D. Molina, I. Monakhov, M. Moneti, R. Mooney, S. Moradi, S. Mordijck, L. Moreira, R. Moreno, F. Moro, A. W. Morris, J. Morris, L. Moser, S. Mosher, D. Moulton, A. Murari, A. Muraro, S. Murphy, N. N. Asakura, Y. S. Na, F. Nabais, R. Naish, T. Nakano, E. Nardon, V. Naulin, M. F. F. Nave, I. Nedzelski, G. Nemtsev, F. Nespoli, A. Neto, R. Neu, V. S. Neverov, M. Newman, K. J. Nicholls, T. Nicolas, A. H. Nielsen, P. Nielsen, E. Nilsson, D. Nishijima, C. Noble, M. Nocente, D. Nodwell, K. Nordlund, H. Nordman, R. Nouailletas, I. Nunes, M. Oberkofler, T. Odupitan, M. T. Ogawa, T. O'Gorman, M. Okabayashi, R. Olney, O. Omolayo, M. O'Mullane, J. Ongena, F. Orsitto, J. Orszagh, B. I. Oswuigwe, R. Otin, A. Owen, R. Paccagnella, N. Pace, D. Pacella, L. W. Packer, A. Page, E. Pajuste, S. Palazzo, S. Pamela, S. Panja, P. Papp, R. Paprok, V. Parail, M. Park, F. Parra Diaz, M. Parsons, R. Pasqualotto, A. Patel, S. Pathak, D. Paton, H. Patten, A. Pau, E. Pawelec, C. Paz Soldan, A. Peackoc, I. J. Pearson, S.-P. Pehkonen, E. Peluso, C. Penot, A. Pereira, R. Pereira, P. P. Pereira Puglia, C. Perez von Thun, S. Peruzzo, S. Peschanyi, M. Peterka, P. Petersson, G. Petravich, A. Petre, N. Petrella, V. Petrzilka, Y. Peysson, D. Pfefferlé, V. Philipps, M. Pillon, G. Pintsuk, P. Piovesan, A. Pires dos Reis, L. Piron, A. Pironti, F. Pisano, R. Pitts, F. Pizzo, V. Plyusnin, N. Pomaro, O. G. Pompilian, P. J. Pool, S. Popovichev, M. T. Porfiri, C. Porosnicu, M. Porton, G. Possnert, S. Potzel, T. Powell, J. Pozzi, V. Prajapati, R. Prakash, G. Prestopino, D. Price, M. Price, R. Price, P. Prior, R. Proudfoot, G. Pucella, P. Puglia, M. E. Puiatti, D. Pulley, K. Purahoo, Th. Pütterich, E. Rachlew, M. Rack, R. Ragona, M. S. J. Rainford, A. Rakha, G. Ramogida, S. Ranjan, C. J. Rapson, J. J. Rasmussen, K. Rathod, G. Rattà, S. Ratynskaia, G. Ravera, C. Rayner, M. Rebai, D. Reece, A. Reed, D. Réfy, B. Regan, J. Regana, M. Reich, N. Reid, F. Reimold, M. Reinhart, M. Reinke, D. Reiser, D. Rendell, C. Reux, S. D. A. Reyes Cortes, S. Reynolds, V. Riccardo, N. Richardson, K. Riddle, D. Rigamonti, F. G. Rimini, J. Risner, M. Riva, C. Roach, R. J. Robins, S. A. Robinson, T. Robinson, D. W. Robson, R. Roccella, R. Rodionov, P. Rodrigues, J. Rodriguez, V. Rohde, F. Romanelli, M. Romanelli, S. Romanelli, J. Romazanov, S. Rowe, M. Rubel, G. Rubinacci, G. Rubino, L. Ruchko, M. Ruiz, C. Ruset, J. Rzadkiewicz, S. Saarelma, R. Sabot, E. Safi, P. Sagar, G. Saibene, F. Saint-Laurent, M. Salewski, A. Salmi, R. Salmon, F. Salzedas, D. Samaddar, U. Samm, D. Sandiford, P. Santa, M. I. K. Santala, B. Santos, A. Santucci, F. Sartori, R. Sartori, O. Sauter, R. Scannell, T. Schlummer, K. Schmid, V. Schmidt, S. Schmuck, M. Schneider, K. Schöpf, D. Schwörer, S. D. Scott, G. Sergienko, M. Sertoli, A. Shabbir, S. E. Sharapov, A. Shaw, R. Shaw, H. Sheikh, A. Shepherd, A. Shevelev, A. Shumack, G. Sias, M. Sibbald, B. Sieglin, S. Silburn, A. Silva, C. Silva, P. A. Simmons, J. Simpson, J. Simpson-Hutchinson, A. Sinha, S. K. Sipilä, A. C. C. Sips, P. Sirén, A. Sirinelli, H. Sjöstrand, M. Skiba, R. Skilton, K. Slabkowska, B. Slade, N. Smith, P. G. Smith, R. Smith, T. J. Smith, M. Smithies, L. Snoj, S. Soare, E. R. Solano, A. Somers, C. Sommariva, P. Sonato, A. Sopplesa, J. Sousa, C. Sozzi, S. Spagnolo, T. Spelzini, F. Spineanu, G. Stables, I. Stamatelatos, M. F. Stamp, P. Staniec, G. Stankunas, C. Stan-Sion, M. J. Stead, E. Stefanikova, I. Stepanov, A. V. Stephen, M. Stephen, A. Stevens, B. D. Stevens, J. Strachan, P. Strand, H. R. Strauss, P. Ström, G. Stubbs, W. Studholme, F. Subba, H. P. Summers, J. Svensson, L. Swiderski, T. Szabolics, M. Szawlowski, G. Szepesi, T. T. Suzuki, B. Tàl, T. Tala, A. R. Talbot, S. Talebzadeh, C. Taliercio, P. Tamain, C. Tame, W. Tang, M. Tardocchi, L. Taroni, D. Taylor, K. A. Taylor, D. Tegnered, G. Telesca, N. Teplova, D. Terranova, D. Testa, E. Tholerus, J. Thomas, J. D. Thomas, P. Thomas, A. Thompson, C.-A. Thompson, V. K. Thompson, L. Thorne, A. Thornton, A. S. Thrysoe, P. A. Tigwell, N. Tipton, I. Tiseanu, H. Tojo, M. Tokitani, P. Tolias, M. Tomes, P. Tonner, M. Towndrow, P. Trimble, M. Tripsky, M. Tsalas, P. Tsavalas, D. Tskhakaya jun, I. Turner, M. M. Turner, M. Turnyanskiy, G. Tvalashvili, S. G. J. Tyrrell, A. Uccello, Z. Ul-Abidin, J. Uljanovs, D. Ulyatt, H. Urano, I. Uytdenhouwen, A. P. Vadgama, D. Valcarcel, M. Valentinuzzi, M. Valisa, P. Vallejos Olivares, M. Valovic, M. Van De Mortel, D. Van Eester, W. Van Renterghem, G. J. van Rooij, J. Varje, S. Varoutis, S. Vartanian, K. Vasava, T. Vasilopoulou, J. Vega, G. Verdoolaege, R. Verhoeven, C. Verona, G. Verona Rinati, E. Veshchev, N. Vianello, J. Vicente, E. Viezzer, S. Villari, F. Villone, P. Vincenzi, I. Vinyar, B. Viola, A. Vitins, Z. Vizvary, M. Vlad, I. Voitsekhovitch, P. Vondràcek, N. Vora, T. Vu, W. W. Pires de Sa, B. Wakeling, C. W. F. Waldon, N. Walkden, M. Walker, R. Walker, M. Walsh, E. Wang, N. Wang, S. Warder, R. J. Warren, J. Waterhouse, N. W. Watkins, C. Watts, T. Wauters, A. Weckmann, J. Weiland, H. Weisen, M. Weiszflog, C. Wellstood, A. T. West, M. R. Wheatley, S. Whetham, A. M. Whitehead, B. D. Whitehead, A. M. Widdowson, S. Wiesen, J. Wilkinson, J. Williams, M. Williams, A. R. Wilson, D. J. Wilson, H. R. Wilson, J. Wilson, M. Wischmeier, G. Withenshaw, A. Withycombe, D. M. Witts, D. Wood, R. Wood, C. Woodley, S. Wray, J. Wright, J. C. Wright, J. Wu, S. Wukitch, A. Wynn, T. Xu, D. Yadikin, W. Yanling, L. Yao, V. Yavorskij, M. G. Yoo, C. Young, D. Young, I. D. Young, R. Young, J. Zacks, R. Zagorski, F. S. Zaitsev, R. Zanino, A. Zarins, K. D. Zastrow, M. Zerbini, W. Zhang, Y. Zhou, E. Zilli, V. Zoita, S. Zoletnik, and I. Zychor
Subjects: Physics, QC1-999
Abstract: A global heat flux model based on a fractional derivative of plasma pressure is proposed for the heat transport in fusion plasmas. The degree of the fractional derivative of the heat flux, α, is defined through the power balance analysis of the steady state. The model was used to obtain the experimental values of α for a large database of the Joint European Torus (JET) carbon-wall as well as ITER like-wall plasmas. The fractional degrees of the electron heat flux are found to be α
Published: 2020
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37. Investigation of plasma wall interactions between tungsten plasma facing components and helium plasmas in the WEST tokamak

Author: E. Tsitrone, B. Pegourie, J.P. Gunn, E. Bernard, V. Bruno, Y. Corre, L. Delpech, M. Diez, D. Douai, A. Ekedahl, N. Fedorczak, A. Gallo, T. Loarer, S. Vartanian, J. Gaspar, M. Le Bohec, F. Rigollet, R. Bisson, S. Brezinsek, T. Dittmar, G. De Temmerman, A. Hakola, T. Wauters, M. Balden, M. Mayer, null WEST Team, CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Forschungszentrum Jülich GmbH, Institut des Hautes Etudes pour l’Innovation et l’Entrepreneuriat (IHEIE) (IHEIE), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratory for Plasma Physics (LPP), Ecole Royale Militaire / Koninklijke Militaire School (ERM KMS), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), and WEST Team
Subjects: [PHYS]Physics [physics], Nuclear and High Energy Physics, Tokamak, Materials science, ITER tungsten divertor, chemistry.chemical_element, Plasma, Tungsten, Condensed Matter Physics, law.invention, chemistry, tungsten plasma facing components, WEST tokamak, law, helium tungsten interactions, Atomic physics, ddc:620, Helium
Abstract: ITER will operate with a tungsten divertor, a material featuring surface morphology changes when exposed to helium plasmas, in particular the formation of the so called tungsten fuzz under specific conditions. Investigating interactions between tungsten plasma facing components and helium plasmas in a tokamak environment is therefore a key point to consolidate predictions for the ITER divertor performance and lifetime. To this end, a dedicated helium campaign was performed in the full tungsten WEST tokamak, cumulating ∼2000 s of repetitive L mode discharges. It is shown that conditions for tungsten fuzz formation, as derived from linear devices experiments (incident helium energy E inc > 20 eV, helium fluence >1024 He/m2, surface temperature T surf > 700 °C), were met in the outer strike point (OSP) area of the inertially cooled tungsten divertor elements of WEST. Preliminary inspection of the components after the campaign did not show visible signs of surface modification, but points to significant net erosion in the OSP area. An extensive post mortem analysis is now ongoing to confirm these first indications. These results underline that the complex balance between erosion/redeposition (in particular linked to impurities) and tungsten fuzz formation needs to be taken into account in tokamak conditions.
Published: 2022

38. Progress from ASDEX Upgrade experiments in preparing the physics basis of ITER operation and DEMO scenario development

Author: U. Stroth, D. Aguiam, E. Alessi, C. Angioni, N. Arden, R. Arredondo Parra, V. Artigues, O. Asunta, M. Balden, V. Bandaru, A. Banon-Navarro, K. Behler, A. Bergmann, M. Bergmann, J. Bernardo, M. Bernert, A. Biancalani, R. Bielajew, R. Bilato, G. Birkenmeier, T. Blanken, V. Bobkov, A. Bock, T. Body, T. Bolzonella, N. Bonanomi, A. Bortolon, B. Böswirth, C. Bottereau, A. Bottino, H. van den Brand, M. Brenzke, S. Brezinsek, D. Brida, F. Brochard, C. Bruhn, J. Buchanan, A. Buhler, A. Burckhart, Y. Camenen, B. Cannas, P. Cano Megias, D. Carlton, M. Carr, P. Carvalho, C. Castaldo, M. Cavedon, C. Cazzaniga, C. Challis, A. Chankin, C. Cianfarani, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, L. Colas, G. Conway, S. Costea, D. Coster, T. Cote, A.J. Creely, G. Croci, D.J. Cruz Zabala, G. Cseh, A. Czarnecka, I. Cziegler, O. D’Arcangelo, A. Dal Molin, P. David, C. Day, M. de Baar, P. de Marné, R. Delogu, S. Denk, P. Denner, A. Di Siena, J.J. Dominguez Palacios Durán, D. Dunai, A. Drenik, M. Dreval, R. Drube, M. Dunne, B.P. Duval, R. Dux, T. Eich, S. Elgeti, A. Encheva, K. Engelhardt, B. Erdös, I. Erofeev, B. Esposito, E. Fable, M. Faitsch, U. Fantz, M. Farnik, H. Faugel, F. Felici, O. Ficker, S. Fietz, A. Figueredo, R. Fischer, O. Ford, L. Frassinetti, M. Fröschle, G. Fuchert, J.C. Fuchs, H. Fünfgelder, S. Futatani, K. Galazka, J. Galdon-Quiroga, D. Gallart Escolà, A. Gallo, Y. Gao, S. Garavaglia, M. Garcia Muñoz, B. Geiger, L. Giannone, S. Gibson, L. Gil, E. Giovannozzi, S. Glöggler, M. Gobbin, J. Gonzalez Martin, T. Goodman, G. Gorini, T. Görler, D. Gradic, G. Granucci, A. Gräter, H. Greuner, M. Griener, M. Groth, A. Gude, L. Guimarais, S. Günter, G. Haas, A.H. Hakola, C. Ham, T. Happel, N. den Harder, G. Harrer, J. Harrison, V. Hauer, T. Hayward-Schneider, B. Heinemann, T. Hellsten, S. Henderson, P. Hennequin, A. Herrmann, E. Heyn, F. Hitzler, J. Hobirk, K. Höfler, J.H. Holm, M. Hölzl, C. Hopf, L. Horvath, T. Höschen, A. Houben, A. Hubbard, A. Huber, K. Hunger, V. Igochine, M. Iliasova, T. Ilkei, K. Insulander Björk, C. Ionita-Schrittwieser, I. Ivanova-Stanik, W. Jacob, N. Jaksic, F. Janky, A. Jansen van Vuuren, A. Jardin, F. Jaulmes, F. Jenko, T. Jensen, E. Joffrin, A. Kallenbach, S. Kálvin, M. Kantor, A. Kappatou, O. Kardaun, J. Karhunen, C.-P. Käsemann, S. Kasilov, A. Kendl, W. Kernbichler, E. Khilkevitch, A. Kirk, S. Kjer Hansen, V. Klevarova, G. Kocsis, M. Koleva, M. Komm, M. Kong, A. Krämer-Flecken, K. Krieger, A. Krivska, O. Kudlacek, T. Kurki-Suonio, B. Kurzan, B. Labit, K. Lackner, F. Laggner, A. Lahtinen, P.T. Lang, P. Lauber, N. Leuthold, L. Li, J. Likonen, O. Linder, B. Lipschultz, Y. Liu, A. Lohs, Z. Lu, T. Luda di Cortemiglia, N.C. Luhmann, T. Lunt, A. Lyssoivan, T. Maceina, J. Madsen, A. Magnanimo, H. Maier, J. Mailloux, R. Maingi, O. Maj, E. Maljaars, P. Manas, A. Mancini, A. Manhard, P. Mantica, M. Mantsinen, P. Manz, M. Maraschek, C. Marchetto, L. Marrelli, P. Martin, A. Martitsch, F. Matos, M. Mayer, M.-L. Mayoral, D. Mazon, P.J. McCarthy, R. McDermott, R. Merkel, A. Merle, D. Meshcheriakov, H. Meyer, D. Milanesio, P. Molina Cabrera, F. Monaco, M. Muraca, F. Nabais, V. Naulin, R. Nazikian, R.D. Nem, A. Nemes-Czopf, G. Neu, R. Neu, A.H. Nielsen, S.K. Nielsen, T. Nishizawa, M. Nocente, J.-M. Noterdaeme, I. Novikau, S. Nowak, M. Oberkofler, R. Ochoukov, J. Olsen, F. Orain, F. Palermo, O. Pan, G. Papp, I. Paradela Perez, A. Pau, G. Pautasso, C. Paz-Soldan, P. Petersson, P. Piovesan, C. Piron, U. Plank, B. Plaum, B. Plöck, V. Plyusnin, G. Pokol, E. Poli, L. Porte, T. Pütterich, M. Ramisch, J. Rasmussen, G. Ratta, S. Ratynskaia, G. Raupp, D. Réfy, M. Reich, F. Reimold, D. Reiser, M. Reisner, D. Reiter, T. Ribeiro, R. Riedl, J. Riesch, D. Rittich, J.F. Rivero Rodriguez, G. Rocchi, P. Rodriguez-Fernandez, M. Rodriguez-Ramos, V. Rohde, G. Ronchi, A. Ross, M. Rott, M. Rubel, D.A. Ryan, F. Ryter, S. Saarelma, M. Salewski, A. Salmi, O. Samoylov, L. Sanchis Sanchez, J. Santos, O. Sauter, G. Schall, K. Schlüter, K. Schmid, O. Schmitz, P.A. Schneider, R. Schrittwieser, M. Schubert, C. Schuster, T. Schwarz-Selinger, J. Schweinzer, E. Seliunin, A. Shabbir, A. Shalpegin, S. Sharapov, U. Sheikh, A. Shevelev, G. Sias, M. Siccinio, B. Sieglin, A. Sigalov, A. Silva, C. Silva, D. Silvagni, J. Simpson, S. Sipilä, E. Smigelskis, A. Snicker, E. Solano, C. Sommariva, C. Sozzi, G. Spizzo, M. Spolaore, A. Stegmeir, M. Stejner, J. Stober, E. Strumberge, G. Suarez Lopez, H.-J. Sun, W. Suttrop, E. Sytova, T. Szepesi, B. Tál, T. Tala, G. Tardini, M. Tardocchi, D. Terranova, M. Teschke, E. Thorén, W. Tierens, D. Told, W. Treutterer, G. Trevisan, E. Trier, M. Tripský, M. Usoltceva, M. Valisa, M. Valovic, M. van Zeeland, F. Vannini, B. Vanovac, P. Varela, S. Varoutis, N. Vianello, J. Vicente, G. Verdoolaege, T. Vierle, E. Viezzer, I. Voitsekhovitch, U. von Toussaint, D. Wagner, X. Wang, M. Weiland, A.E. White, M. Willensdorfer, B. Wiringer, M. Wischmeier, R. Wolf, E. Wolfrum, Q. Yang, Q. Yu, R. Zagórski, I. Zammuto, T. Zehetbauer, W. Zhang, W. Zholobenko, M. Zilker, A. Zito, H. Zohm, S. Zoletnik, the EUROfusion MST1 Team, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Aix Marseille Université (AMU), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), EUROfusion MST1 Team, Barcelona Supercomputing Center, Department of Applied Physics, Aalto-yliopisto, Aalto University, Stroth, U, Aguiam, D, Alessi, E, Angioni, C, Arden, N, Parra, R, Artigues, V, Asunta, O, Balden, M, Bandaru, V, Banon-Navarro, A, Behler, K, Bergmann, A, Bergmann, M, Bernardo, J, Bernert, M, Biancalani, A, Bielajew, R, Bilato, R, Birkenmeier, G, Blanken, T, Bobkov, V, Bock, A, Body, T, Bolzonella, T, Bonanomi, N, Bortolon, A, Boswirth, B, Bottereau, C, Bottino, A, Van Den Brand, H, Brenzke, M, Brezinsek, S, Brida, D, Brochard, F, Bruhn, C, Buchanan, J, Buhler, A, Burckhart, A, Camenen, Y, Cannas, B, Megias, P, Carlton, D, Carr, M, Carvalho, P, Castaldo, C, Cavedon, M, Cazzaniga, C, Challis, C, Chankin, A, Cianfarani, C, Clairet, F, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, Cote, T, Creely, A, Croci, G, Zabala, D, Cseh, G, Czarnecka, A, Cziegler, I, D'Arcangelo, O, Molin, A, David, P, Day, C, De Baar, M, De Marne, P, Delogu, R, Denk, S, Denner, P, Di Siena, A, Palacios Duran, J, Dunai, D, Drenik, A, Dreval, M, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Encheva, A, Engelhardt, K, Erdos, B, Erofeev, I, Esposito, B, Fable, E, Faitsch, M, Fantz, U, Farnik, M, Faugel, H, Felici, F, Ficker, O, Fietz, S, Figueredo, A, Fischer, R, Ford, O, Frassinetti, L, Froschle, M, Fuchert, G, Fuchs, J, Funfgelder, H, Futatani, S, Galazka, K, Galdon-Quiroga, J, Escola, D, Gallo, A, Gao, Y, Garavaglia, S, Munoz, M, Geiger, B, Giannone, L, Gibson, S, Gil, L, Giovannozzi, E, Gloggler, S, Gobbin, M, Martin, J, Goodman, T, Gorini, G, Gorler, T, Gradic, D, Granucci, G, Grater, A, Greuner, H, Griener, M, Groth, M, Gude, A, Guimarais, L, Gunter, S, Haas, G, Hakola, A, Ham, C, Happel, T, Den Harder, N, Harrer, G, Harrison, J, Hauer, V, Hayward-Schneider, T, Heinemann, B, Hellsten, T, Henderson, S, Hennequin, P, Herrmann, A, Heyn, E, Hitzler, F, Hobirk, J, Hofler, K, Holm, J, Holzl, M, Hopf, C, Horvath, L, Hoschen, T, Houben, A, Hubbard, A, Huber, A, Hunger, K, Igochine, V, Iliasova, M, Ilkei, T, Bjork, K, Ionita-Schrittwieser, C, Ivanova-Stanik, I, Jacob, W, Jaksic, N, Janky, F, Jansen Van Vuuren, A, Jardin, A, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Kallenbach, A, Kalvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kasemann, C, Kasilov, S, Kendl, A, Kernbichler, W, Khilkevitch, E, Kirk, A, Hansen, S, Klevarova, V, Kocsis, G, Koleva, M, Komm, M, Kong, M, Kramer-Flecken, A, Krieger, K, Krivska, A, Kudlacek, O, Kurki-Suonio, T, Kurzan, B, Labit, B, Lackner, K, Laggner, F, Lahtinen, A, Lang, P, Lauber, P, Leuthold, N, Li, L, Likonen, J, Linder, O, Lipschultz, B, Liu, Y, Lohs, A, Lu, Z, Luda Di Cortemiglia, T, Luhmann, N, Lunt, T, Lyssoivan, A, Maceina, T, Madsen, J, Magnanimo, A, Maier, H, Mailloux, J, Maingi, R, Maj, O, Maljaars, E, Manas, P, Mancini, A, Manhard, A, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Marchetto, C, Marrelli, L, Martin, P, Martitsch, A, Matos, F, Mayer, M, Mayoral, M, Mazon, D, Mccarthy, P, Mcdermott, R, Merkel, R, Merle, A, Meshcheriakov, D, Meyer, H, Milanesio, D, Cabrera, P, Monaco, F, Muraca, M, Nabais, F, Naulin, V, Nazikian, R, Nem, R, Nemes-Czopf, A, Neu, G, Neu, R, Nielsen, A, Nielsen, S, Nishizawa, T, Nocente, M, Noterdaeme, J, Novikau, I, Nowak, S, Oberkofler, M, Ochoukov, R, Olsen, J, Orain, F, Palermo, F, Pan, O, Papp, G, Perez, I, Pau, A, Pautasso, G, Paz-Soldan, C, Petersson, P, Piovesan, P, Piron, C, Plank, U, Plaum, B, Plock, B, Plyusnin, V, Pokol, G, Poli, E, Porte, L, Putterich, T, Ramisch, M, Rasmussen, J, Ratta, G, Ratynskaia, S, Raupp, G, Refy, D, Reich, M, Reimold, F, Reiser, D, Reisner, M, Reiter, D, Ribeiro, T, Riedl, R, Riesch, J, Rittich, D, Rodriguez, J, Rocchi, G, Rodriguez-Fernandez, P, Rodriguez-Ramos, M, Rohde, V, Ronchi, G, Ross, A, Rott, M, Rubel, M, Ryan, D, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Samoylov, O, Sanchez, L, Santos, J, Sauter, O, Schall, G, Schluter, K, Schmid, K, Schmitz, O, Schneider, P, Schrittwieser, R, Schubert, M, Schuster, C, Schwarz-Selinger, T, Schweinzer, J, Seliunin, E, Shabbir, A, Shalpegin, A, Sharapov, S, Sheikh, U, Shevelev, A, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Silvagni, D, Simpson, J, Sipila, S, Smigelskis, E, Snicker, A, Solano, E, Sommariva, C, Sozzi, C, Spizzo, G, Spolaore, M, Stegmeir, A, Stejner, M, Stober, J, Strumberge, E, Lopez, G, Sun, H, Suttrop, W, Sytova, E, Szepesi, T, Tal, B, Tala, T, Tardini, G, Tardocchi, M, Terranova, D, Teschke, M, Thoren, E, Tierens, W, Told, D, Treutterer, W, Trevisan, G, Trier, E, Tripsky, M, Usoltceva, M, Valisa, M, Valovic, M, Van Zeeland, M, Vannini, F, Vanovac, B, Varela, P, Varoutis, S, Vianello, N, Vicente, J, Verdoolaege, G, Vierle, T, Viezzer, E, Voitsekhovitch, I, Von Toussaint, U, Wagner, D, Wang, X, Weiland, M, White, A, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Yang, Q, Yu, Q, Zagorski, R, Zammuto, I, Zehetbauer, T, Zhang, W, Zholobenko, W, Zilker, M, Zito, A, Zohm, H, and Zoletnik, S
Subjects: Nuclear and High Energy Physics, Asdex Upgrade, confinement, ELLM-free discharges, sol, Computer science, Nuclear engineering, ALCATOR C-MOD, UPPER DIVERTOR, ASDEX Upgrade, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Simulació per ordinador, alcator c-mod, ddc:530, upper divertor, ELLM-free discharge, SOL, Basis (linear algebra), Physics, turbulence, transition, h-mode plasmas, Condensed Matter Physics, ddc, Informàtica::Aplicacions de la informàtica::Aplicacions informàtiques a la física i l‘enginyeria [Àrees temàtiques de la UPC], Fusion reactors, Physics and Astronomy, CONFINEMENT MODES, H-MODE PLASMAS, Physics::Space Physics, Nuclear fusion, TURBULENCE, ddc:620, confinement modes, TRANSITION
Abstract: An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling of AUG discharges was established which is able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In the plasma center, theoretical predictions on plasma current redistribution by a dynamo effect were confirmed experimentally. For core transport, the stabilizing effect of fast ion distributions on turbulent transport is shown to be important to explain the core isotope effect and improves the description of hollow low-Z impurity profiles. The L–H power threshold of hydrogen plasmas is not affected by small helium admixtures and it increases continuously from the deuterium to the hydrogen level when the hydrogen concentration is raised from 0 to 100%. One focus of recent campaigns was the search for a fusion relevant integrated plasma scenario without large edge localised modes (ELMs). Results from six different ELM-free confinement regimes are compared with respect to reactor relevance: ELM suppression by magnetic perturbation coils could be attributed to toroidally asymmetric turbulent fluctuations in the vicinity of the separatrix. Stable improved confinement mode plasma phases with a detached inner divertor were obtained using a feedback control of the plasma β. The enhanced Dα H-mode regime was extended to higher heating power by feedback controlled radiative cooling with argon. The quasi-coherent exhaust regime was developed into an integrated scenario at high heating power and energy confinement, with a detached divertor and without large ELMs. Small ELMs close to the separatrix lead to peeling-ballooning stability and quasi continuous power exhaust. Helium beam density fluctuation measurements confirm that transport close to the separatrix is important to achieve the different ELM-free regimes. Based on separatrix plasma parameters and interchange-drift-Alfvén turbulence, an analytic model was derived that reproduces the experimentally found important operational boundaries of the density limit and between L- and H-mode confinement. Feedback control for the X-point radiator (XPR) position was established as an important element for divertor detachment control. Stable and detached ELM-free phases with H-mode confinement quality were obtained when the XPR was moved 10 cm above the X-point. Investigations of the plasma in the future flexible snow-flake divertor of AUG by means of first SOLPS-ITER simulations with drifts activated predict beneficial detachment properties and the activation of an additional strike point by the drifts. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under Grant Agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Peer Reviewed "Article signat per més de 50 autors/es: U. Stroth, D. Aguiam, E. Alessi, C. Angioni, N. Arden, R. Arredondo Parra, V. Artigues, O. Asunta, M. Balden, V. Bandaru, A. Banon-Navarro, K. Behler, A. Bergmann, M. Bergmann, J. Bernardo, M. Bernert, A. Biancalani, R. Bielajew, R. Bilato, G. Birkenmeier, T. Blanken, V. Bobkov, A. Bock, T. Body, T. Bolzonella, N. Bonanomi, A. Bortolon, B. Böswirth, C. Bottereau, A. Bottino, H. van den Brand, M. Brenzke, S. Brezinsek, D. Brida, F. Brochard, C. Bruhn, J. Buchanan, A. Buhler, A. Burckhart, Y. Camenen, B. Cannas, P. Cano Megias, D. Carlton, M. Carr, P. Carvalho, C. Castaldo, M. Cavedon, C. Cazzaniga, C. Challis, A. Chankin, C. Cianfarani, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, L. Colas, G. Conway, S. Costea, D. Coster, T. Cote, A.J. Creely, G. Croci, D.J. Cruz Zabala, G. Cseh, A. Czarnecka, I. Cziegler, O. D'Arcangelo, A. Dal Molin, P. David, C. Day, M. de Baar, P. de Marné, R. Delogu, S. Denk, P. Denner, A. Di Siena, J.J. Dominguez Palacios Durán, D. Dunai, A. Drenik, M. Dreval, R. Drube, M. Dunne, B.P. Duval, R. Dux, T. Eich, S. Elgeti, A. Encheva, K. Engelhardt, B. Erdös, I. Erofeev, B. Esposito, E. Fable, M. Faitsch, U. Fantz, M. Farnik, H. Faugel, F. Felici, O. Ficker, S. Fietz, A. Figueredo, R. Fischer, O. Ford, L. Frassinetti, M. Fröschle, G. Fuchert, J.C. Fuchs, H. Fünfgelder, S. Futatani, K. Galazka, J. Galdon-Quiroga, D. Gallart Escolà, A. Gallo10, Y. Gao11, S. Garavaglia3, M. Garcia Muñoz16, B. Geiger21, L. Giannone1, S. Gibson32, L. Gil2, E. Giovannozzi18, S. Glöggler1, M. Gobbin8, J. Gonzalez Martin, T. Goodman, G. Gorini, T. Görler, D. Gradic, G. Granucci, A. Gräter, H. Greuner, M. Griener, M. Groth, A. Gude, L. Guimarais, S. Günter, G. Haas, A.H. Hakola, C. Ham, T. Happel, N. den Harder, G. Harrer, J. Harrison, V. Hauer, T. Hayward-Schneider, B. Heinemann, T. Hellsten, S. Henderson, P. Hennequin, A. Herrmann, E. Heyn, F. Hitzler, J. Hobirk, K. Höfler, J.H. Holm, M. Hölzl, C. Hopf, L. Horvath, T. Höschen, A. Houben, A. Hubbard, A. Huber, K. Hunger, V. Igochine, M. Iliasova, T. Ilkei, K. Insulander Björk, C. Ionita-Schrittwieser, I. Ivanova-Stanik, W. Jacob, N. Jaksic, F. Janky, A. Jansen van Vuuren, A. Jardin, F. Jaulmes, F. Jenko, T. Jensen, E. Joffrin, A. Kallenbach, S. Kálvin, M. Kantor, A. Kappatou, O. Kardaun, J. Karhunen4, C.-P. Käsemann, S. Kasilov, A. Kendl, W. Kernbichler, E. Khilkevitch, A. Kirk, S. Kjer Hansen, V. Klevarova, G. Kocsis, M. Koleva, M. Komm, M. Kong, A. Krämer-Flecken, K. Krieger, A. Krivska, O. Kudlacek, T. Kurki-Suonio, B. Kurzan, B. Labit, K. Lackner, F. Laggner, A. Lahtinen, P.T. Lang, P. Lauber, N. Leuthold, L. Li, J. Likonen, O. Linder, B. Lipschultz, Y. Liu, A. Lohs, Z. Lu, T. Luda di Cortemiglia, N.C. Luhmann, T. Lunt, A. Lyssoivan, T. Maceina, J. Madsen, A. Magnanimo, H. Maier, J. Mailloux, R. Maingi, O. Maj, E. Maljaars, P. Manas, A. Mancini, A. Manhard, P. Mantica, M. Mantsinen, P. Manz, M. Maraschek, C. Marchetto, L. Marrelli, P. Martin, A. Martitsch, F. Matos, M. Mayer, M.-L. Mayoral, D. Mazon, P.J. McCarthy, R. McDermott, R. Merkel, A. Merle, D. Meshcheriakov, H. Meyer, D. Milanesio, P. Molina Cabrera, F. Monaco, M. Muraca, F. Nabais, V. Naulin, R. Nazikian, R.D. Nem, A. Nemes-Czopf, G. Neu, R. Neu, A.H. Nielsen, S.K. Nielsen, T. Nishizawa, M. Nocente, J.-M. Noterdaeme, I. Novikau, S. Nowak, M. Oberkofler, R. Ochoukov, J. Olsen, F. Orain, F. Palermo, O. Pan, G. Papp, I. Paradela Perez, A. Pau, G. Pautasso, C. Paz-Soldan, P. Petersson, P. Piovesan, C. Piron, U. Plank, B. Plaum, B. Plöck, V. Plyusnin, G. Pokol, E. Poli, L. Porte, T. Pütterich, M. Ramisch, J. Rasmussen, G. Ratta, S. Ratynskaia, G. Raupp, D. Réfy, M. Reich1, F. Reimold, D. Reiser, M. Reisner, D. Reiter, T. Ribeiro, R. Riedl, J. Riesch, D. Rittich, J.F. Rivero Rodriguez, G. Rocchi, P. Rodriguez-Fernandez, M. Rodriguez-Ramos, V. Rohde, G. Ronchi, A. Ross, M. Rott, M. Rubel, D.A. Ryan, F. Ryter, S. Saarelma, M. Salewski, A. Salmi, O. Samoylov, L. Sanchis Sanchez, J. Santos, O. Sauter, G. Schall, K. Schlüter, K. Schmid, O. Schmitz, P.A. Schneider, R. Schrittwieser, M. Schubert, C. Schuster, T. Schwarz-Selinger, J. Schweinzer, E. Seliunin, A. Shabbir, A. Shalpegin, S. Sharapov, U. Sheikh, A. Shevelev, G. Sias, M. Siccinio, B. Sieglin, A. Sigalov, A. Silva, C. Silva, D. Silvagni, J. Simpson, S. Sipilä, E. Smigelskis, A. Snicker, E. Solano, C. Sommariva, C. Sozzi, G. Spizzo, M. Spolaore, A. Stegmeir, M. Stejner, J. Stober, E. Strumberge1, G. Suarez Lopez, H.-J. Sun, W. Suttrop, E. Sytova, T. Szepesi, B. Tál, T. Tala, G. Tardini, M. Tardocchi, D. Terranova, M. Teschke, E. Thorén, W. Tierens, D. Told, W. Treutterer, G. Trevisan, E. Trier, M. Tripský, M. Usoltceva, M. Valisa, M. Valovic, M. van Zeeland, F. Vannini, B. Vanovac, P. Varela, S. Varoutis, N. Vianello, J. Vicente, G. Verdoolaege, T. Vierle, E. Viezzer, I. Voitsekhovitch, U. von Toussaint, D. Wagner, X. Wang, M. Weiland, A.E. White, M. Willensdorfer, B. Wiringer, M. Wischmeier, R. Wolf, E. Wolfrum, Q. Yang, Q. Yu, R. Zagórski, I. Zammuto, T. Zehetbauer, W. Zhang, W. Zholobenko, M. Zilker, A. Zito, H. Zohm, S. Zoletnik and the EUROfusion MST1 Team "
Published: 2022

39. Plasma-surface interaction in the stellarator W7-X: conclusions drawn from operation with graphite plasma-facing components

Author: S. BrezƖnsek, C.P. Dhard, M. Jakubowski, R. König, S. Masuzaki, M. Mayer, D. Naujoks, J. Romazanov, K. Schmid, O. Schmitz, D. Zhao, M. Balden, R. Brakel, B. Butterschoen, T. Dittmar, P. Drews, F. Effenberg, S. Elgeti, O. Ford, E. Fortuna-Zalesna, G. Fuchert, Y. Gao, A. Goriaev, A. Hakola, T. Kremeyer, M. Krychowiak, Y. Liang, Ch. Linsmeier, R. Lunsford, G. Motojima, R. Neu, O. Neubauer, J. Oelmann, P. Petersson, M. Rasinski, M. Rubel, S. Sereda, G. Sergienko, T. Sunn Pedersen, T. Vuoriheimo, E. Wang, T. Wauters, V. Winters, M. Zhao, R. Yi, null the W7-X Team, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society
Subjects: Nuclear and High Energy Physics, Materials science, graphite, Plasma surface interaction, Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, material migration, erosion and deposition, law, 0103 physical sciences, Wendelstein 7-X, Graphite, Atomic physics, ddc:620, 010306 general physics, Stellarator, plasma surface interactions
Abstract: W7-X completed its plasma operation in hydrogen with island divertor and inertially cooled test divertor unit (TDU) made of graphite. A substantial set of plasma-facing components (PFCs), including in particular marker target elements, were extracted from the W7-X vessel and analysed post-mortem. The analysis provided key information about underlying plasma–surface interactions (PSI) processes, namely erosion, transport, and deposition as well as fuel retention in the graphite components. The net carbon (C) erosion and deposition distribution on the horizontal target (HT) and vertical target (VT) plates were quantified and related to the plasma time in standard divertor configuration with edge transform ι = 5/5, the dominant magnetic configuration of the two operational phases (OP) with TDU. The operation resulted in integrated high net C erosion rate of 2.8 mg s−1 in OP1.2B over 4809 plasma seconds. Boronisations reduced the net erosion on the HT by about a factor 5.4 with respect to OP1.2A owing to the suppression of oxygen (O). In the case of the VT, high peak net C erosion of 11 μm at the strike line was measured during OP1.2B which converts to 2.5 nm s−1 or 1.4 mg s−1 when related to the exposed area of the target plate and the operational time in standard divertor configuration. PSI modelling with ERO2.0 and WallDYN-3D is applied in an interpretative manner and reproduces the net C erosion and deposition pattern at the target plates determined by different post-mortem analysis techniques. This includes also the 13C tracer deposition from the last experiment of OP1.2B with local 13CH4 injection through a magnetic island in one half module. The experimental findings are used to predict the C erosion, transport, and deposition in the next campaigns aiming in long-pulse operation up to 1800 s and utilising the actively cooled carbon-fibre composite (CFC) divertor currently being installed. The CFC divertor has the same geometrical design as the TDU and extrapolation depends mainly on the applied plasma boundary. Extrapolation from campaign averaged information obtained in OP1.2B reveals a net erosion of 7.6 g per 1800 s for a typical W7-X attached divertor plasma in hydrogen.
Published: 2022

40. Progress in additive manufacturing of pure tungsten for plasma-facing component applications

Author: A.v. Müller, D. Dorow-Gerspach, M. Balden, M. Binder, B. Buschmann, B. Curzadd, T. Loewenhoff, R. Neu, G. Schlick, J.H. You, and Publica
Subjects: Nuclear and High Energy Physics, Nuclear Energy and Engineering, Additive manufacturing, Laser powder bed fusion, Plasma-facing component, General Materials Science, ddc:620, Refractory metal, Tungsten
Abstract: In the present paper, recent progress regarding additive manufacturing (AM) of pure tungsten (W) by means of laser powder bed fusion (LPBF) is discussed. In this context, several aspects are highlighted: The influence of the raw powder material characteristics on the resulting W part quality is briefly discussed, examples for complexly shaped additively manufactured W lattice structure samples are shown, the application of an additively manufactured W structure as preform for a tungsten-copper (W-Cu) composite is illustrated and thermal shock experiments on additively manufactured bulk W samples with the electron beam facility JUDITH 2 are described. The latter demonstrates that W material consolidated by means of LPBF is capable of surviving intense thermal shock loads. This is an encouraging result indicating that the thermal performance and stability of W fabricated by means of LPBF is comparable to that of conventionally fabricated W which in turn implies that the further investigation of additively manufactured W as candidate material with regard to applications in highly loaded plasma-facing components (PFCs) of future magnetic confinement thermonuclear fusion devices can be considered worthwhile.
Published: 2022

41. Carbon erosion/deposition on the divertor of W7-X during the operational period OP 1.2b

Author: M. Mayer, M. Balden, S. Brezinsek, V.V. Burwitz, C. Cupak, C.P. Dhard, S. Elgeti, M. Guitart Corominas, P. Hiret, M. Kandler, D. Naujoks, J.-H. Schmidt-Dencker, C. Ruset, T.B. Saramela, T.F. Silva, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society
Subjects: Nuclear and High Energy Physics, ddc:620, Condensed Matter Physics
Abstract: Carbon net erosion and deposition at the test divertor unit (TDU) of Wendelstein 7-X (W7-X) were measured for the discharge period OP 1.2b in the year 2018 using 18 specially prepared target elements in all 10 TDUs. These had lengths between 30 and 60 cm and were coated with marker layers for erosion/deposition investigations of 5–10 μm carbon on top of about 300 nm molybdenum. The marker layer thicknesses were measured by elastic backscattering spectrometry (EBS) before and after plasma exposure using 2.5 MeV protons; the surface morphology was investigated using scanning electron microscopy (SEM) and focused ion beam cross-sectioning (FIB), the surface roughness was determined using a two-dimensional optical profiler. Plasma-exposed surfaces were considerably smoother than unexposed surfaces with decreased mean roughness and a shift of the inclination angle distribution towards lower values. The erosion on the 10 TDUs was unequal within a factor of about two. During the discharge period in total 20.4 ± 5.7 g carbon was eroded from the 10 TDUs. Adjacent to the strike line some deposition of carbon was observed. Compared to the discharge period OP 1.2a in the year 2017, the net carbon erosion rate dropped by a factor of 5–6 due to regular boronizations, which reduced the oxygen (and subsequently also the carbon) content in the plasma by 1–2 orders of magnitude. The significance of erosion/deposition processes for long-pulse discharges is discussed.
Published: 2022

42. Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

Author: Thomas Sunn Pedersen, I. Abramovic, P. Agostinetti, M. Agredano Torres, S. Äkäslompolo, J. Alcuson Belloso, P. Aleynikov, K. Aleynikova, M. Alhashimi, A. Ali, N. Allen, A. Alonso, G. Anda, T. Andreeva, C. Angioni, A. Arkhipov, A. Arnold, W. Asad, E. Ascasibar, M.-H. Aumeunier, K. Avramidis, E. Aymerich, S.-G. Baek, J. Bähner, A. Baillod, M. Balden, J. Baldzuhn, S. Ballinger, M. Banduch, S. Bannmann, A. Banon Navarro, A. Bañón Navarro, T. Barbui, C. Beidler, C. Belafdil, A. Bencze, A. Benndorf, M. Beurskens, C. Biedermann, O. Biletskyi, B. Blackwell, M. Blatzheim, T. Bluhm, D. Böckenhoff, G. Bongiovi, M. Borchardt, D. Borodin, J. Boscary, H. Bosch, T. Bosmann, B. Böswirth, L. Böttger, A. Bottino, S. Bozhenkov, R. Brakel, C. Brandt, T. Bräuer, H. Braune, S. Brezinsek, K. Brunner, S. Buller, R. Burhenn, R. Bussiahn, B. Buttenschön, A. Buzás, V. Bykov, I. Calvo, K. Camacho Mata, I. Caminal, B. Cannas, A. Cappa, A. Carls, F. Carovani, M. Carr, D. Carralero, B. Carvalho, J. Casas, D. Castano-Bardawil, F. Castejon, N. Chaudhary, I. Chelis, A. Chomiczewska, J.W. Coenen, M. Cole, F. Cordella, Y. Corre, K. Crombe, G. Cseh, B. Csillag, H. Damm, C. Day, M. de Baar, E. De la Cal, S. Degenkolbe, A. Demby, S. Denk, C. Dhard, A. Di Siena, A. Dinklage, T. Dittmar, M. Dreval, M. Drevlak, P. Drewelow, P. Drews, D. Dunai, E. Edlund, F. Effenberg, G. Ehrke, M. Endler, D.A. Ennis, F.J. Escoto, T. Estrada, E. Fable, N. Fahrenkamp, A. Fanni, J. Faustin, J. Fellinger, Y. Feng, W. Figacz, E. Flom, O. Ford, T. Fornal, H. Frerichs, S. Freundt, G. Fuchert, M. Fukuyama, F. Füllenbach, G. Gantenbein, Y. Gao, K. Garcia, J.M. García Regaña, I. García-Cortés, J. Gaspar, D.A. Gates, J. Geiger, B. Geiger, L. Giudicotti, A. González, A. Goriaev, D. Gradic, M. Grahl, J.P. Graves, J. Green, E. Grelier, H. Greuner, S. Groß, H. Grote, M. Groth, M. Gruca, O. Grulke, M. Grün, J. Guerrero Arnaiz, S. Günter, V. Haak, M. Haas, P. Hacker, A. Hakola, A. Hallenbert, K. Hammond, X. Han, S.K. Hansen, J.H. Harris, H. Hartfuß, D. Hartmann, D. Hathiramani, R. Hatzky, J. Hawke, S. Hegedus, B. Hein, B. Heinemann, P. Helander, S. Henneberg, U. Hergenhahn, C. Hidalgo, F. Hindenlang, M. Hirsch, U. Höfel, K.P. Hollfeld, A. Holtz, D. Hopf, D. Höschen, M. Houry, J. Howard, X. Huang, M. Hubeny, S. Hudson, K. Ida, Y. Igitkhanov, V. Igochine, S. Illy, C. Ionita-Schrittwieser, M. Isobe, M. Jabłczyńska, S. Jablonski, B. Jagielski, M. Jakubowski, A. Jansen van Vuuren, J. Jelonnek, F. Jenko, T. Jensen, H. Jenzsch, P. Junghanns, J. Kaczmarczyk, J. Kallmeyer, U. Kamionka, M. Kandler, S. Kasilov, Y. Kazakov, D. Kennedy, A. Kharwandikar, M. Khokhlov, C. Kiefer, C. Killer, A. Kirschner, R. Kleiber, T. Klinger, S. Klose, J. Knauer, A. Knieps, F. Köchl, G. Kocsis, Ya.I. Kolesnichenko, A. Könies, R. König, J. Kontula, P. Kornejew, J. Koschinsky, M.M. Kozulia, A. Krämer-Flecken, R. Krampitz, M. Krause, N. Krawczyk, T. Kremeyer, L. Krier, D.M. Kriete, M. Krychowiak, I. Ksiazek, M. Kubkowska, M. Kuczynski, G. Kühner, A. Kumar, T. Kurki-Suonio, S. Kwak, M. Landreman, P.T. Lang, A. Langenberg, H.P. Laqua, H. Laqua, R. Laube, S. Lazerson, M. Lewerentz, C. Li, Y. Liang, Ch. Linsmeier, J. Lion, A. Litnovsky, S. Liu, J. Lobsien, J. Loizu, J. Lore, A. Lorenz, U. Losada, F. Louche, R. Lunsford, V. Lutsenko, M. Machielsen, F. Mackel, J. Maisano-Brown, O. Maj, D. Makowski, G. Manduchi, E. Maragkoudakis, O. Marchuk, S. Marsen, E. Martines, J. Martinez-Fernandez, M. Marushchenko, S. Masuzaki, D. Maurer, M. Mayer, K.J. McCarthy, O. Mccormack, P. McNeely, H. Meister, B. Mendelevitch, S. Mendes, A. Merlo, A. Messian, A. Mielczarek, O. Mishchenko, B. Missal, R. Mitteau, V.E. Moiseenko, A. Mollen, V. Moncada, T. Mönnich, T. Morisaki, D. Moseev, G. Motojima, S. Mulas, M. Mulsow, M. Nagel, D. Naujoks, V. Naulin, T. Neelis, H. Neilson, R. Neu, O. Neubauer, U. Neuner, D. Nicolai, S.K. Nielsen, H. Niemann, T. Nishiza, T. Nishizawa, C. Nührenberg, R. Ochoukov, J. Oelmann, G. Offermanns, K. Ogawa, S. Okamura, J. Ölmanns, J. Ongena, J. Oosterbeek, M. Otte, N. Pablant, N. Panadero Alvarez, A. Pandey, E. Pasch, R. Pavlichenko, A. Pavone, E. Pawelec, G. Pechstein, G. Pelka, V. Perseo, B. Peterson, D. Pilopp, S. Pingel, F. Pisano, B. Plöckl, G. Plunk, P. Pölöskei, B. Pompe, A. Popov, M. Porkolab, J. Proll, M.J. Pueschel, M.-E. Puiatti, A. Puig Sitjes, F. Purps, K. Rahbarnia, M. Rasiński, J. Rasmussen, A. Reiman, F. Reimold, M. Reisner, D. Reiter, M. Richou, R. Riedl, J. Riemann, K. Riße, G. Roberg-Clark, V. Rohde, J. Romazanov, D. Rondeshagen, P. Rong, L. Rudischhauser, T. Rummel, K. Rummel, A. Runov, N. Rust, L. Ryc, P. Salembier, M. Salewski, E. Sanchez, S. Satake, G. Satheeswaran, J. Schacht, E. Scharff, F. Schauer, J. Schilling, G. Schlisio, K. Schmid, J. Schmitt, O. Schmitz, W. Schneider, M. Schneider, P. Schneider, R. Schrittwieser, T. Schröder, M. Schröder, R. Schroeder, B. Schweer, D. Schwörer, E. Scott, B. Shanahan, G. Sias, P. Sichta, M. Singer, P. Sinha, S. Sipliä, C. Slaby, M. Sleczka, H. Smith, J. Smoniewski, E. Sonnendrücker, M. Spolaore, A. Spring, R. Stadler, D. Stańczak, T. Stange, I. Stepanov, L. Stephey, J. Stober, U. Stroth, E. Strumberger, C. Suzuki, Y. Suzuki, J. Svensson, T. Szabolics, T. Szepesi, M. Szücs, F.L. Tabarés, N. Tamura, A. Tancetti, C. Tantos, J. Terry, H. Thienpondt, H. Thomsen, M. Thumm, J.M. Travere, P. Traverso, J. Tretter, E. Trier, H. Trimino Mora, T. Tsujimura, Y. Turkin, A. Tykhyi, B. Unterberg, P. van Eeten, B.Ph. van Milligen, M. van Schoor, L. Vano, S. Varoutis, M. Vecsei, L. Vela, J.L. Velasco, M. Vervier, N. Vianello, H. Viebke, R. Vilbrandt, G. Vogel, N. Vogt, C. Volkhausen, A. von Stechow, F. Wagner, E. Wang, H. Wang, F. Warmer, T. Wauters, L. Wegener, T. Wegner, G. Weir, U. Wenzel, A. White, F. Wilde, F. Wilms, T. Windisch, M. Winkler, A. Winter, V. Winters, R. Wolf, A.M. Wright, G.A. Wurden, P. Xanthopoulos, S. Xu, H. Yamada, H. Yamaguchi, M. Yokoyama, M. Yoshinuma, Q. Yu, M. Zamanov, M. Zanini, M. Zarnstorff, D. Zhang, S. Zhou, J. Zhu, C. Zhu, M. Zilker, A. Zocco, H. Zohm, S. Zoletnik, L. Zsuga, Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. GPI - Grup de Processament d'Imatge i Vídeo, Universitat Politècnica de Catalunya. GREO - Grup de Recerca en Enginyeria Òptica, Pedersen, T, Abramovic, I, Agostinetti, P, Torres, M, Akaslompolo, S, Belloso, J, Aleynikov, P, Aleynikova, K, Alhashimi, M, Ali, A, Allen, N, Alonso, A, Anda, G, Andreeva, T, Angioni, C, Arkhipov, A, Arnold, A, Asad, W, Ascasibar, E, Aumeunier, M, Avramidis, K, Aymerich, E, Baek, S, Bahner, J, Baillod, A, Balden, M, Baldzuhn, J, Ballinger, S, Banduch, M, Bannmann, S, Navarro, A, Barbui, T, Beidler, C, Belafdil, C, Bencze, A, Benndorf, A, Beurskens, M, Biedermann, C, Biletskyi, O, Blackwell, B, Blatzheim, M, Bluhm, T, Bockenhoff, D, Bongiovi, G, Borchardt, M, Borodin, D, Boscary, J, Bosch, H, Bosmann, T, Boswirth, B, Bottger, L, Bottino, A, Bozhenkov, S, Brakel, R, Brandt, C, Brauer, T, Braune, H, Brezinsek, S, Brunner, K, Buller, S, Burhenn, R, Bussiahn, R, Buttenschon, B, Buzas, A, Bykov, V, Calvo, I, Mata, K, Caminal, I, Cannas, B, Cappa, A, Carls, A, Carovani, F, Carr, M, Carralero, D, Carvalho, B, Casas, J, Castano-Bardawil, D, Castejon, F, Chaudhary, N, Chelis, I, Chomiczewska, A, Coenen, J, Cole, M, Cordella, F, Corre, Y, Crombe, K, Cseh, G, Csillag, B, Damm, H, Day, C, de Baar, M, De la Cal, E, Degenkolbe, S, Demby, A, Denk, S, Dhard, C, Di Siena, A, Dinklage, A, Dittmar, T, Dreval, M, Drevlak, M, Drewelow, P, Drews, P, Dunai, D, Edlund, E, Effenberg, F, Ehrke, G, Endler, M, Ennis, D, Escoto, F, Estrada, T, Fable, E, Fahrenkamp, N, Fanni, A, Faustin, J, Fellinger, J, Feng, Y, Figacz, W, Flom, E, Ford, O, Fornal, T, Frerichs, H, Freundt, S, Fuchert, G, Fukuyama, M, Fullenbach, F, Gantenbein, G, Gao, Y, Garcia, K, Regana, J, Garcia-Cortes, I, Gaspar, J, Gates, D, Geiger, J, Geiger, B, Giudicotti, L, Gonzalez, A, Goriaev, A, Gradic, D, Grahl, M, Graves, J, Green, J, Grelier, E, Greuner, H, Gross, S, Grote, H, Groth, M, Gruca, M, Grulke, O, Grun, M, Arnaiz, J, Gunter, S, Haak, V, Haas, M, Hacker, P, Hakola, A, Hallenbert, A, Hammond, K, Han, X, Hansen, S, Harris, J, Hartfuss, H, Hartmann, D, Hathiramani, D, Hatzky, R, Hawke, J, Hegedus, S, Hein, B, Heinemann, B, Helander, P, Henneberg, S, Hergenhahn, U, Hidalgo, C, Hindenlang, F, Hirsch, M, Hofel, U, Hollfeld, K, Holtz, A, Hopf, D, Hoschen, D, Houry, M, Howard, J, Huang, X, Hubeny, M, Hudson, S, Ida, K, Igitkhanov, Y, Igochine, V, Illy, S, Ionita-Schrittwieser, C, Isobe, M, Jablczynska, M, Jablonski, S, Jagielski, B, Jakubowski, M, van Vuuren, A, Jelonnek, J, Jenko, F, Jensen, T, Jenzsch, H, Junghanns, P, Kaczmarczyk, J, Kallmeyer, J, Kamionka, U, Kandler, M, Kasilov, S, Kazakov, Y, Kennedy, D, Kharwandikar, A, Khokhlov, M, Kiefer, C, Killer, C, Kirschner, A, Kleiber, R, Klinger, T, Klose, S, Knauer, J, Knieps, A, Kochl, F, Kocsis, G, Kolesnichenko, Y, Konies, A, Konig, R, Kontula, J, Kornejew, P, Koschinsky, J, Kozulia, M, Kramer-Flecken, A, Krampitz, R, Krause, M, Krawczyk, N, Kremeyer, T, Krier, L, Kriete, D, Krychowiak, M, Ksiazek, I, Kubkowska, M, Kuczynski, M, Kuhner, G, Kumar, A, Kurki-Suonio, T, Kwak, S, Landreman, M, Lang, P, Langenberg, A, Laqua, H, Laube, R, Lazerson, S, Lewerentz, M, Li, C, Liang, Y, Linsmeier, C, Lion, J, Litnovsky, A, Liu, S, Lobsien, J, Loizu, J, Lore, J, Lorenz, A, Losada, U, Louche, F, Lunsford, R, Lutsenko, V, Machielsen, M, Mackel, F, Maisano-Brown, J, Maj, O, Makowski, D, Manduchi, G, Maragkoudakis, E, Marchuk, O, Marsen, S, Martines, E, Martinez-Fernandez, J, Marushchenko, M, Masuzaki, S, Maurer, D, Mayer, M, Mccarthy, K, Mccormack, O, Mcneely, P, Meister, H, Mendelevitch, B, Mendes, S, Merlo, A, Messian, A, Mielczarek, A, Mishchenko, O, Missal, B, Mitteau, R, Moiseenko, V, Mollen, A, Moncada, V, Monnich, T, Morisaki, T, Moseev, D, Motojima, G, Mulas, S, Mulsow, M, Nagel, M, Naujoks, D, Naulin, V, Neelis, T, Neilson, H, Neu, R, Neubauer, O, Neuner, U, Nicolai, D, Nielsen, S, Niemann, H, Nishiza, T, Nishizawa, T, Nuhrenberg, C, Ochoukov, R, Oelmann, J, Offermanns, G, Ogawa, K, Okamura, S, Olmanns, J, Ongena, J, Oosterbeek, J, Otte, M, Pablant, N, Alvarez, N, Pandey, A, Pasch, E, Pavlichenko, R, Pavone, A, Pawelec, E, Pechstein, G, Pelka, G, Perseo, V, Peterson, B, Pilopp, D, Pingel, S, Pisano, F, Plockl, B, Plunk, G, Poloskei, P, Pompe, B, Popov, A, Porkolab, M, Proll, J, Pueschel, M, Puiatti, M, Sitjes, A, Purps, F, Rahbarnia, K, Rasinski, M, Rasmussen, J, Reiman, A, Reimold, F, Reisner, M, Reiter, D, Richou, M, Riedl, R, Riemann, J, Risse, K, Roberg-Clark, G, Rohde, V, Romazanov, J, Rondeshagen, D, Rong, P, Rudischhauser, L, Rummel, T, Rummel, K, Runov, A, Rust, N, Ryc, L, Salembier, P, Salewski, M, Sanchez, E, Satake, S, Satheeswaran, G, Schacht, J, Scharff, E, Schauer, F, Schilling, J, Schlisio, G, Schmid, K, Schmitt, J, Schmitz, O, Schneider, W, Schneider, M, Schneider, P, Schrittwieser, R, Schroder, T, Schroder, M, Schroeder, R, Schweer, B, Schworer, D, Scott, E, Shanahan, B, Sias, G, Sichta, P, Singer, M, Sinha, P, Siplia, S, Slaby, C, Sleczka, M, Smith, H, Smoniewski, J, Sonnendrucker, E, Spolaore, M, Spring, A, Stadler, R, Stanczak, D, Stange, T, Stepanov, I, Stephey, L, Stober, J, Stroth, U, Strumberger, E, Suzuki, C, Suzuki, Y, Svensson, J, Szabolics, T, Szepesi, T, Szucs, M, Tabares, F, Tamura, N, Tancetti, A, Tantos, C, Terry, J, Thienpondt, H, Thomsen, H, Thumm, M, Travere, J, Traverso, P, Tretter, J, Trier, E, Mora, H, Tsujimura, T, Turkin, Y, Tykhyi, A, Unterberg, B, van Eeten, P, van Milligen, B, van Schoor, M, Vano, L, Varoutis, S, Vecsei, M, Vela, L, Velasco, J, Vervier, M, Vianello, N, Viebke, H, Vilbrandt, R, Vogel, G, Vogt, N, Volkhausen, C, von Stechow, A, Wagner, F, Wang, E, Wang, H, Warmer, F, Wauters, T, Wegener, L, Wegner, T, Weir, G, Wenzel, U, White, A, Wilde, F, Wilms, F, Windisch, T, Winkler, M, Winter, A, Winters, V, Wolf, R, Wright, A, Wurden, G, Xanthopoulos, P, Xu, S, Yamada, H, Yamaguchi, H, Yokoyama, M, Yoshinuma, M, Yu, Q, Zamanov, M, Zanini, M, Zarnstorff, M, Zhang, D, Zhou, S, Zhu, J, Zhu, C, Zilker, M, Zocco, A, Zohm, H, Zoletnik, S, Zsuga, L, Fusion and Plasma Physics, Department of Applied Physics, National Institute for Fusion Science, Aalto-yliopisto, Aalto University, Science and Technology of Nuclear Fusion, Group Heemels, Control Systems Technology, and Turbulence in Fusion Plasmas
Subjects: Magnetic confinement, Nuclear and High Energy Physics, Technology, Materials science, Detachment, Nuclear engineering, Física::Física de partícules [Àrees temàtiques de la UPC], Imatges -- Processament, stellarator, Divertor, Image processing, Physics::Plasma Physics, divertor, Wendelstein 7-X, ddc:530, FIS/03 - FISICA DELLA MATERIA, Neoclassical optimization, Stellarators, Reactors de fusió, magnetic confinement, Enginyeria de la telecomunicació::Processament del senyal::Processament de la imatge i del senyal vídeo [Àrees temàtiques de la UPC], Condensed Matter Physics, ddc, Fusion reactors, Physics and Astronomy, detachment, neoclassical optimization, ddc:620, ddc:600, Paper, FEC 2020 Summaries and Overviews
Abstract: We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under Grant Agreement No. 633053. Peer Reviewed Article signat per 497 autors/es: Thomas Sunn Pedersen1,2,∗ , I. Abramovic3, P. Agostinetti4, M. Agredano Torres1, S. Äkäslompolo1, J. Alcuson Belloso1, P. Aleynikov1, K. Aleynikova1, M. Alhashimi1, A. Ali1, N. Allen5, A. Alonso6, G. Anda7, T. Andreeva1, C. Angioni8, A. Arkhipov8, A. Arnold1, W. Asad8, E. Ascasibar6, M.-H. Aumeunier9, K. Avramidis10, E. Aymerich11, S.-G. Baek3, J. Bähner1, A. Baillod12, M. Balden1, M. Balden8, J. Baldzuhn1, S. Ballinger3, M. Banduch1, S. Bannmann1, A. Banon Navarro8, A. Bañon Navarro ´ 1, T. Barbui13, C. Beidler1, C. Belafdil9, A. Bencze7, A. Benndorf1, M. Beurskens1, C. Biedermann1, O. Biletskyi14, B. Blackwell15, M. Blatzheim1, T. Bluhm1, D. Böckenhoff1, G. Bongiovi16, M. Borchardt1, D. Borodin17, J. Boscary8, H. Bosch1,18, T. Bosmann19, B. Böswirth8, L. Böttger1, A. Bottino8, S. Bozhenkov1, R. Brakel1, C. Brandt1, T. Bräuer1, H. Braune1, S. Brezinsek17, K. Brunner1, S. Buller1, R. Burhenn1, R. Bussiahn1, B. Buttenschön1, A. Buzás7, V. Bykov1, I. Calvo6, K. Camacho Mata1, I. Caminal20, B. Cannas11, A. Cappa6, A. Carls1, F. Carovani1, M. Carr21, D. Carralero6, B. Carvalho22, J. Casas20, D. Castano-Bardawil17, F. Castejon6, N. Chaudhary1, I. Chelis23, A. Chomiczewska24, J.W. Coenen13,17, M. Cole1, F. Cordella25, Y. Corre9, K. Crombe26, G. Cseh7, B. Csillag7, H. Damm1, C. Day10, M. de Baar27, E. De la Cal6, S. Degenkolbe1, A. Demby13, S. Denk3, C. Dhard1, A. Di Siena8,28, A. Dinklage12, T. Dittmar17, M. Dreval14, M. Drevlak1, P. Drewelow1, P. Drews17, D. Dunai7, E. Edlund3, F. Effenberg29, G. Ehrke1, M. Endler1, D.A. Ennis5, F.J. Escoto6, T. Estrada6, E. Fable8, N. Fahrenkamp1, A. Fanni11, J. Faustin1, J. Fellinger1, Y. Feng1, W. Figacz4, E. Flom13, O. Ford1, T. Fornal24, H. Frerichs13, S. Freundt1, G. Fuchert1, M. Fukuyama30, F. Füllenbach1, G. Gantenbein10, Y. Gao1, K. Garcia13, J.M. García Regaña6, I. García-Cortés6, J. Gaspar31, D.A. Gates29, J. Geiger1, B. Geiger13, L. Giudicotti32, A. González6, A. Goriaev26,33, D. Gradic1, M. Grahl1, J.P. Graves12, J. Green13, E. Grelier9, H. Greuner8, S. Groß1, H. Grote1, M. Groth34, M. Gruca24, O. Grulke1,35, M. Grün1, J. Guerrero Arnaiz1, S. Günter8, V. Haak1, M. Haas1, P. Hacker1, A. Hakola36, A. Hallenbert1, K. Hammond29, X. Han17,37, S.K. Hansen3, J.H. Harris38, H. Hartfuß1, D. Hartmann1, D. Hathiramani1, R. Hatzky8, J. Hawke39, S. Hegedus7, B. Hein8, B. Heinemann8, P. Helander12, S. Henneberg1, U. Hergenhahn8,40, C. Hidalgo6, F. Hindenlang8, M. Hirsch1, U. Höfel1, K.P. Hollfeld17, A. Holtz1, D. Hopf8, D. Höschen17, M. Houry9, J. Howard19, X. Huang41, M. Hubeny17, S. Hudson29, K. Ida9, Y. Igitkhanov10, V. Igochine8, S. Illy10, C. Ionita-Schrittwieser42, M. Isobe39, M. Jabłczynska ´ 24, S. Jablonski24, B. Jagielski1, M. Jakubowski1, A. Jansen van Vuuren1, J. Jelonnek10, F. Jenko8, F. Jenko8, T. Jensen35, H. Jenzsch1, P. Junghanns8, J. Kaczmarczyk24, J. Kallmeyer1, U. Kamionka1, M. Kandler8, S. Kasilov43, Y. Kazakov26, D. Kennedy1, A. Kharwandikar1, M. Khokhlov1, C. Kiefer8, C. Killer1, A. Kirschner17, R. Kleiber1, T. Klinger12, S. Klose1, J. Knauer1, A. Knieps17, F. Köchl44, G. Kocsis7, Ya.I. Kolesnichenko45, A. Könies1, R. König1, J. Kontula34, P. Kornejew1, J. Koschinsky, M.M. Kozulia14, A. Krämer-Flecken17, R. Krampitz1, M. Krause1, N. Krawczyk24, T. Kremeyer1, L. Krier10, D.M. Kriete5, M. Krychowiak1, I. Ksiazek46, M. Kubkowska24, M. Kuczynski1, G. Kühner1, A. Kumar15, T. Kurki-Suonio34, S. Kwak1, M. Landreman47, P.T. Lang8, A. Langenberg1, H.P. Laqua12, H. Laqua1, R. Laube1, S. Lazerson1, M. Lewerentz1, C. Li17, Y. Liang17, Ch. Linsmeier17, J. Lion1, A. Litnovsky17,48, S. Liu37, J. Lobsien1, J. Loizu12, J. Lore38, A. Lorenz1, U. Losada6, F. Louche26, R. Lunsford29, V. Lutsenko45, M. Machielsen12, F. Mackel8, J. Maisano-Brown3, O. Maj8, D. Makowski49, G. Manduchi50, E. Maragkoudakis6, O. Marchuk17, S. Marsen1, E. Martines4, J. Martinez-Fernandez6, M. Marushchenko1, S. Masuzaki41, D. Maurer5, M. Mayer8, K.J. McCarthy6, O. Mccormack4, P. McNeely1, H. Meister8, B. Mendelevitch8, S. Mendes1, A. Merlo1, A. Messian26, A. Mielczarek49, O. Mishchenko1, B. Missal1, R. Mitteau9, V.E. Moiseenko14, A. Mollen1, V. Moncada9, T. Mönnich1, T. Morisaki41, D. Moseev1, G. Motojima41, S. Mulas6, M. Mulsow1, M. Nagel1, D. Naujoks1, V. Naulin35, T. Neelis19, H. Neilson29, R. Neu8, O. Neubauer17, U. Neuner1, D. Nicolai17, S.K. Nielsen35, H. Niemann1, T. Nishiza1, T. Nishizawa1, T. Nishizawa8, C. Nührenberg1, R. Ochoukov8, J. Oelmann17, G. Offermanns17 K. Ogawa41, S. Okamura41, J. Ölmanns17, J. Ongena26, J. Oosterbeek1, M. Otte1, N. Pablant29, N. Panadero Alvarez6, N. Panadero Alvarez6, A. Pandey1, E. Pasch1, R. Pavlichenko14, A. Pavone1, E. Pawelec46, G. Pechstein1, G. Pelka24, V. Perseo1, B. Peterson41, D. Pilopp1, S. Pingel1, F. Pisano11, B. Plöckl8, G. Plunk1, P. Pölöskei1, B. Pompe2, A. Popov51, M. Porkolab3, J. Proll19, M.J. Pueschel19,27, M.-E. Puiatti52, A. Puig Sitjes1, F. Purps1, K. Rahbarnia1, M. Rasinski ´ 17, J. Rasmussen35, A. Reiman29, F. Reimold1, M. Reisner8, D. Reiter17, M. Richou9, R. Riedl8, J. Riemann1, K. Riße1, G. Roberg-Clark1, V. Rohde8, J. Romazanov17, D. Rondeshagen1, P. Rong1, L. Rudischhauser1, T. Rummel1, K. Rummel1, A. Runov1, N. Rust1, L. Ryc24, P. Salembier20, M. Salewski35, E. Sanchez6, S. Satake41, G. Satheeswaran17, J. Schacht1, E. Scharff1, F. Schauer8, J. Schilling1, G. Schlisio1, K. Schmid8, J. Schmitt5, O. Schmitz13, W. Schneider1, M. Schneider1, P. Schneider8, R. Schrittwieser42, T. Schröder1, M. Schröder1, R. Schroeder1, B. Schweer26, D. Schwörer1, E. Scott1, E. Scott8, B. Shanahan1, G. Sias11, P. Sichta29, M. Singer1, P. Sinha29, S. Sipliä34, C. Slaby1, M. Sleczka53, H. Smith1, J. Smoniewski54, E. Sonnendrücker8, M. Spolaore4, A. Spring1, R. Stadler8, D. Stanczak24, T. Stange1, I. Stepanov26, L. Stephey13, J. Stober8, U. Stroth8,55, E. Strumberger8, C. Suzuki41, Y. Suzuki41, J. Svensson1, T. Szabolics7, T. Szepesi7, M. Szücs7, F.L. Tabares6, N. Tamura41, A. Tancetti35, C. Tantos10, J. Terry3, H. Thienpondt6, H. Thomsen1, M. Thumm10, J.M. Travere9, P. Traverso5, J. Tretter8, E. Trier8, H. Trimino Mora1, T. Tsujimura41, Y. Turkin1, A. Tykhyi45, B. Unterberg17, P. van Eeten1, B.Ph. van Milligen6, M. van Schoor26, L. Vano1, S. Varoutis10, M. Vecsei7, L. Vela56, J.L. Velasco6, M. Vervier17, N. Vianello50, H. Viebke1, R. Vilbrandt1, G. Vogel8, N. Vogt1, C. Volkhausen1, A. von Stechow1, F. Wagner1, E. Wang17, H. Wang57, F. Warmer1, T. Wauters26, L. Wegener1, T. Wegner1, G. Weir1, U. Wenzel1, A. White3, F. Wilde1, F. Wilms1, T. Windisch1, M. Winkler1, A. Winter1, V. Winters1, R. Wolf118, A.M. Wright29, G.A. Wurden39, P. Xanthopoulos1, S. Xu17, H. Yamada58, H. Yamaguchi41, M. Yokoyama41, M. Yoshinuma41, Q. Yu8, M. Zamanov14, M. Zanini1, M. Zarnstorff29, D. Zhang1, S. Zhou17, J. Zhu1, C. Zhu29, M. Zilker8, A. Zocco1, H. Zohm8, S. Zoletnik7 and L. Zsuga7 // 1 Max Planck Institute for Plasma Physics, Garching and Greifswald, Germany: 2 University of Greifswald, Greifswald, Germany; 3 Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States of America; 4 Consorzio RFX, Corso Stati Uniti, 4-35127 Padova, Italy; 5 Auburn University, Auburn, AL 36849, United States of America; 6 CIEMAT, Avenida Complutense, 40, 28040 Madrid, Spain; 7 Center for Energy Research, Konkoly-Thegeut 29-33, 1121 Budapest, Hungary; 8 Max-Planck-Institute for Plasma Physics, Boltzmannstraße 2, 85748 Garching bei München, Germany; 9 CEA Cadarache, 13115 Saint-Paul-lez-Durance, France; 10 Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany; 11 University of Cagliari, Via Universita, 40, 09124 Cagliari, Italy; 12 École Polytechnique Fédérale de Lausanne, Swiss Plasma Center, CH-1015 Lausanne, Switzerland; 13 University of Wisconsin–Madison, Engineering Drive, Madison, WI 53706, United States of America; 14 Institute of Plasma Physics, National Science Center ‘Kharkiv Institute of Physics and Technology’, Kharkiv, Ukraine; 15 The Australian National University, Acton ACT 2601, Canberra, Australia; 16 Department of Engineering, University of Palermo, Viale delle Scienze, Edificio 6, Palermo, 90128, Italy; 17 Forschungszentrum Jülich GmbH, Institut für Energie-und Klimaforschung—Plasmaphysik, 52425 Jülich, Germany; 18 Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany; 19 Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands; 20 Universitat Politècnica de Catalunya. BarcelonaTech, C. Jordi Girona, 31, 08034 Barcelona, Spain; 21 Culham Center for Fusion Energy, Abingdon OX14 3EB, United Kingdom; 22 Instituto de Plasmas e Fusao Nuclear, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; 23 Department of Physics, National and Kapodistrian University of Athens, 15784 Athens, Greece; 24 Institute of Plasma Physics and Laser Microfusion, 23 Hery Str., 01-497 Warsaw, Poland; 25 ENEA—Centro Ricerche Frascati, Via Enrico Fermi, 45, 00044 Frascati RM, Italy; 26 Laboratory for Plasma Physics, LPP-ERM/KMS, TEC Partner, B-1000 Brussels, Belgium; 27 Dutch Institute for Fundamental Energy Research, PO Box 6336, 5600 HH Eindhoven, Netherlands; 28 University of Texas, Austin, TX, United States of America; 29 Princeton Plasma Physics Laboratory, Princeton, NJ 08543, United States of America; 30 Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395, Japan; 31 Aix-Marseille University, Jardin du Pharo, 58 Boulevard Charles Livon, 13007, Marseille, France; 32 Department of Physics and Astronomy, Padova University, Via Marzolo 8, 35131 Padova, Italy; 33 Department of Applied Physics, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent, Belgium; 34 Aalto University, 02150 Espoo, Finland; 35 Department of Physics, Technical University of Denmark, Anker Engelunds Vej, 2800 Kgs Lyngby, Denmark; 36 VTT Technical Research Center of Finland Ltd., PO Box 1000, FI-02044 VTT, Finland; 37 Institute of Plasma Physics, Chinese Academy of Sciences, 230031 Hefei, Anhui, China; 38 Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37830, United States of America; 39 Los Alamos National Laboratory, NM 87545, United States of America; 40 Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany; 41 National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki, Gifu Prefecture 509-5292, Japan; 42 Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria; 43 Graz University of Technology, Rechbauerstraße 12, 8010 GRAZ, Austria; 44 Austrian Academy of Science, Doktor-Ignaz-Seipel-Platz 2, 1010 Wien, Austria; 45 Institute for Nuclear Research, prospekt Nauky 47, Kyiv 03028, Ukraine; 46 University of Opole, plac Kopernika 11a, 45-001 Opole, Poland; 47 University of Maryland, Paint Branch Drive, College Park, MA 20742, United States of America; 48 National Research Nuclear University MEPhI, 115409 Moscow, Russian Federation; 49 Department of Microelectronics and Computer Science, Lodz University of Technology, Wolczanska 221/223, 90-924 Lodz, Poland; 50 Consiglio Nazionale delle Ricerche, Piazzale Aldo Moro, 7, 00185 Roma, Italy; 51 Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 26 Politekhnicheskaya, St Petersburg 194021, Russian Federation; 52 Istituto di Fisica del Plasma Piero Caldirola, Via Roberto Cozzi, 53, 20125 Milano, Italy; 53 University of Szczecin, 70-453, aleja Papieza Jana Pawła II 22A, Szczecin, Poland; 54 Lawrence University, 711 E Boldt Way, Appleton, WI 54911, United States of America; 55 Physik-Department E28, Technische Universität München, 85747 Garching, Germany; 56 Universidad Carlos III de Madrid, Av. de la Universidad, 30 Madrid, Spain; 57 Yale University, New Haven, CT 06520, United States of America; 58 University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chhiab 277-0882, Japan Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.a - Per a 2030, augmentar la cooperació internacional per tal de facilitar l’accés a la investigació i a les tecnologies energètiques no contaminants, incloses les fonts d’energia renovables, l’eficiència energètica i les tecnologies de combustibles fòssils avançades i menys contaminants, i promoure la inversió en infraestructures energètiques i tecnologies d’energia no contaminant
Published: 2022
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43. Erosion and redeposition patterns on entire erosion marker tiles after exposure in the first operation phase of WEST

Author: Céline Martin, M. Firdaouss, M. Richou, M. Balden, B. Pégourié, H. Roche, M. Mayer, B. Bliewert, M. Diez, Marc Missirlian, E. Tsitrone, Antti Hakola, E. Bernard, Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and WEST Team
Subjects: Tungsten fuzz, WEST, SEM and EDX, Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, Arcing, 010305 fluids & plasmas, [SPI.MAT]Engineering Sciences [physics]/Materials, RBS and NRA, Plasma-wall interaction, Phase (matter), 0103 physical sciences, Erosion, Erosion and deposition, 010301 acoustics, Geomorphology, Mathematical Physics, Geology
Abstract: The net erosion and deposition patterns in the inner and outer divertor of WEST were determined after different experimental campaigns (C3 and C4) of the first operational phase using ion beam analyses and scanning electron microscopy techniques. The analyses were performed on four entire tiles from inertially cooled, W-coated divertor units with an additional Mo marker coating covered with a further W coating. Strong erosion occurred at the expected location of the inner and outer strike line area with a campaign-averaged net erosion rate of >0.1 nm s−1. On the high field side of the inner strike line area, thick deposited layers were found (>10 μm; growth rate >1 nm s−1), mainly composed of B, C, O, and W. Additionally, strong arcing was observed in this region. At the end of the C4 campaign, He discharges were performed to study the He-W interaction. Although the conditions for nanotendrils, i.e. fuzz formation were fulfilled around the outer strike line position, neither nanotendrils nor He bubbles (>10 nm) were observed at this area.
Published: 2021

44. Properties of Droplets Emitted from Vacuum Arc Cathodes Made of Copper, Tungsten and Titanium

Author: M. Balden, Jurgen Sachtleben, Michael Laux, Peter Siemroth, V. Rohde, R. Neu, and Heinz Pursch
Subjects: Materials science, Particle number, chemistry.chemical_element, Vacuum arc, Power law, Cathode, Light scattering, law.invention, chemistry, law, Particle, Atomic physics, Copper–tungsten, Titanium
Abstract: Molten droplets emitted from the cathode of vacuum arcs have been investigated by using a time-of-flight setup along a vertical flight tube equipped with two light barriers at different distances from the cathode surface. The light scattered by particles passing the light barriers was registered. The velocity was determined by the flight time. Simultaneously, from the amount of the scattered light, the size of the passing particle was inferred by applying the Mie-scattering theory. Because the arrangement of the cathode could be oriented concerning the flight tube, a coarse angular distribution of the parameters was obtained. Due to a large amount of data, computerized processing by newly developed algorithms was required to identify and characterize the several tens of thousands of particle peaks. The number of particles per discharge depends strongly on the cathode material and varies remarkably with the angle between flight direction and cathode surface. Generally, smaller particles were found to have higher velocities and vice versa. The distribution of the particle sizes follows a power law. The distribution of the emission velocities exhibits more than one local maximum pointing to distinct particle populations having distinct typical velocities. These populations contribute differently to the total amount of particles at various angles.
Published: 2021

45. Overview of first Wendelstein 7-X high-performance operation

Author: V. Moncada, S. C. Liu, M. Winkler, P. Pölöskei, A. Tancetti, Naoki Tamura, H. Neilson, M. Krychowiak, Michael Drevlak, K. H. Schlüter, S. A. Henneberg, R. Vilbrandt, N. A. Pablant, M. Schröder, B. van Milligen, Bernd Heinemann, K. Rummel, Jonathan Schilling, Torsten Stange, G. Orozco, Christian Brandt, N. Krawczyk, Suguru Masuzaki, Yunfeng Liang, T. Estrada, Wolfgang Biel, J. H. Harris, B. Unterberg, M. Sleczka, M. Marushchenko, R. Lang, N. Rust, J. P. Kallmeyer, Laurie Stephey, P. Aleynikov, E. Blanco, Hans-Stephan Bosch, B. Buttenschön, D. Mellein, B. Shanahan, M. Vervier, M. Yokoyama, C. Suzuki, Seung Gyou Baek, A. Lücke, Felix Schauer, Ya. I. Kolesnichenko, V. Borsuk, Th. Rummel, B. Gonçalves, R. König, H. P. Laqua, G. Ehrke, K. J. McCarthy, Manfred Zilker, Venanzio Giannella, O. P. Ford, E. Flom, S. Murakami, Andreas Schlaich, P. Xanthopoulos, M. Zanini, E. Ascasíbar, C. Nührenberg, A. Carls, H. Viebke, Y. Feng, A. da Molin, H. Hunger, S. Paqay, Y. Wei, M. Blatzheim, M. W. Jakubowski, F. Köster, T. Wauters, J.C. Schmitt, M. Hubeny, P. van Eeten, H. Damm, Joris Fellinger, Gábor Cseh, Christoph Biedermann, G. Claps, L. Rudischhauser, R. Stadler, J. Mittelstaedt, Matteo Zuin, Z. Szökefalvi-Nagy, M. Knaup, Ch. Linsmeier, Francisco Castejón, J. P. Koschinsky, Bernardo B. Carvalho, L. Wegener, C. Guerard, J.M. Hernández Sánchez, B. Mendelevitch, A. Grosman, S. Pingel, Horacio Fernandes, M. Endler, N. Vianello, Jörg Schacht, Anett Spring, Yu Gao, V. Rohde, Samuel Lazerson, J.H. Matthew, W. Kasparek, R. Neu, R. Burhenn, N. Panadero, Jörg Weggen, P.A. Kurz, Walter H. Fietz, R. Schroeder, Andrea Pavone, G. Offermanns, Ryo Yasuhara, P. Sinha, Massimiliano Romé, José Luis Velasco, Carsten Killer, P. Drewelow, X. Han, T. Windisch, Nengchao Wang, Axel Könies, E.M. Edlund, K. P. Hollfeld, K. Aleynikova, Malte Henkel, Detlev Reiter, S. Brezinsek, Z. Huang, Heinz Grote, S. Langish, Matthias Otte, Alessandro Zocco, Daniel Papenfuß, G. Satheeswaran, Monika Kubkowska, S. Obermayer, G. A. Wurden, Carsten Lechte, F. Wagner, M. Gruca, H. Zhang, Olaf Neubauer, Peter Traverso, T. Ngo, V. Bykov, E. Sánchez, Matt Landreman, Dirk Naujoks, I. Vakulchyk, Andreas Langenberg, E. Wang, B. Hein, I. Ksiazek, S. Valet, Mark Cianciosa, G. Schlisio, Taina Kurki-Suonio, Oliver Schmitz, Adnan Ali, F. Reimold, Shinsuke Satake, Luis Vela Vela, C. Slaby, F. Remppel, David Gates, S. Schmuck, B. Roth, Zhirui Wang, Heinrich P. Laqua, F. Schluck, Olaf Grulke, S. Wadle, A. Runov, Manfred Thumm, Florian Effenberg, G. Fuchert, A. Vorköper, M. Banduch, Jonathan T. Green, J. Nührenberg, F. V. Chernyshev, H. Braune, Ewa Pawelec, David Maurer, A. Winter, A. Charl, Hiroshi Kasahara, T. Mizuuchi, D. Zhang, D. Höschen, J. Riemann, Thomas Klinger, W. Leonhardt, S. Sipliä, Katsumi Ida, T. Jesche, G. Pelka, U. Stridde, Riccardo Nocentini, Alexandra M. Freund, P. McNeely, A. Gogoleva, Victoria Winters, V. Szabó, Wolf-Dieter Schneider, D. A. Hartmann, Fabian Wilde, H. Schumacher, J. Howard, A. van Vuuren, J.L. Terry, M. Nagel, C. Hidalgo, Georg Kühner, S. Wolf, Boyd Blackwell, Michael Cole, Barbara Cannas, D. Rondeshagen, P. Hacker, Torsten Bluhm, J. Kacmarczyk, Kunihiro Ogawa, A. Zeitler, I. Yamada, P. Rong, Tamara Andreeva, Hiroshi Yamada, G. Anda, N. Panadero Alvarez, Wilfried Behr, F. Purps, H. Esteban, Dag Hathiramani, R. Bussiahn, David Ennis, A. H. Reiman, D. R. Mikkelsen, M. Borchardt, B. Israeli, M. Grahl, M. Losert, T. Dittmar, E. Pasch, U. Kamionka, Toru Ii Tsujimura, Gabriel G. Plunk, Felix Warmer, Jeremy Lore, F. Durodié, M. Balden, B.J. Peterson, J.P. Bähner, R. Schrittwieser, Morten Stejner, M.J. Cole, S. Zoletnik, Kian Rahbarnia, O. Marchuk, T. Bräuer, M. Hirsch, R. Riedl, W. Figacz, H. Trimino Mora, S. Degenkolbe, H. Greuner, B. Böswirth, B. Schweer, Dorothea Gradic, S. B. Ballinger, S. Ryosuke, B. Missal, Jiawu Zhu, J. H. E. Proll, M. Czerwinski, A. Cappa, B. Wiegel, J. Loizu Cisquella, Per Helander, Sehyun Kwak, S. Marsen, L. Carraro, T. Ilkei, D. Pilopp, Gábor Náfrádi, S. Récsei, M. Houry, A. de la Peña, Yu. Turkin, T.A. Scherer, T. Schröder, A. Galkowski, P. Drews, H. Frerichs, Benedikt Geiger, A. Krämer-Flecken, M. Dibon, L.-G. Böttger, A. Czarnecka, R. Krampitz, J. Wendorf, N. Chaudhary, T. Kremeyer, A. da Silva, R. Kleiber, R. Sakamoto, J.-M. Travere, I. Abramovic, T. Funaba, Andreas Meier, Fabio Pisano, Holger Niemann, Mirko Salewski, R. Brakel, M. Mayer, X. Huang, Stefan Illy, Ph. Mertens, Naoki Kenmochi, F. Köchl, Peter Lang, J. Geiger, Albert Mollén, A. Hölting, T. Barbui, M. Lennartz, T. Szabolics, Hayato Tsuchiya, S. Renard, A. Lorenz, J. Krom, C. D. Beidler, J. Cai, Andreas Dinklage, Anne White, Ye. O. Kazakov, P. Junghanns, W. Spiess, J. M. García Regaña, S. Elgeti, J. W. Coenen, Thomas Sunn Pedersen, C. Li, T. Mönnich, Miklos Porkolab, R. Laube, Burkhard Plaum, A. Benndorf, Michael Kramer, J. Ongena, J. Svensson, Dmitry Moseev, U. Wenzel, Chandra Prakash Dhard, S. Tulipán, M. C. Zarnstorff, M. Sibilia, A. von Stechow, G. M. Weir, H. Maaßberg, U. Höfel, P. Scholz, Alexey Mishchenko, R. C. Wolf, D. Carralero, G. Kocsis, Ivan Calvo, J. Tretter, Didier Chauvin, Y. Li, J. Boscary, A. Puig Sitjes, Fumimichi Sano, Andrey Samartsev, Tamás Szepesi, A. Kirschner, Dirk Nicolai, Francesco Cordella, M. Rack, A. Alonso, G. Czymek, E. R. Scott, M. E. Puiatti, Stefan Kragh Nielsen, M. Vergote, H. Schmitz, H. Jenzsch, Donald A. Spong, K. Czerski, A. Knieps, Arnold Lumsdaine, L. Ryć, M. N. A. Beurskens, Matthias F. Schneider, Simppa Äkäslompolo, Ulrich Neuner, V. Perseo, Jim-Felix Lobsien, Gerd Gantenbein, Roberto Guglielmo Citarella, L. Pacios Rodriguez, L. Vano, S. Bozhenkov, J. W. Oosterbeek, H. Röhlinger, J. P. Knauer, T. Nishizawa, A.H. Wright, M. Jia, A. Goriaev, H. Brand, D. Böckenhoff, H. M. Smith, J. P. Thomas, T. Fornal, J. Baldzuhn, D. Loesser, K. Risse, John Jelonnek, T. Wegner, S. Jablonski, Martina Huber, V. V. Lutsenko, S. Sereda, J. Ölmanns, Tomohiro Morisaki, H. Thomsen, J. A. Alcuson, P. Kornejew, J M Fontdecaba, Kai Jakob Brunner, A. Werner, T. Kobarg, European Commission, University of Greifswald, Max Planck Institute for Plasma Physics, Technical University of Denmark, Princeton University, National Institute for Fusion Science, CIEMAT, EURATOM HAS, Massachusetts Institute of Technology, University of Wisconsin-Madison, Research Center Julich, Australian National University, Eindhoven University of Technology, University of Cagliari, Consorzio RFX, Universidade de Lisboa, CEA Cadarache, St. Petersburg Scientific Centre, Oak Ridge National Laboratory, University of Salerno, ENEA Frascati Research Center, Institute of Plasma Physics and Laser Microfusion, University of Szczecin, University of Milano-Bicocca, Auburn University, Karlsruhe Institute of Technology, Universidad Carlos III de Madrid, University of Stuttgart, Austrian Academy of Sciences, National Academy of Sciences Ukraine, Technical University of Berlin, Opole University of Technology, Fusion and Plasma Physics, University of Maryland College Park, Consiglio Nazionale delle Ricerche (CNR), Kyoto University, Culham Centre for Fusion Energy, Physikalisch-Technische Bundesanstalt, Los Alamos National Laboratory, Department of Applied Physics, Aalto-yliopisto, and Aalto University
Subjects: Technology, CONFINEMENT, 01 natural sciences, impurities, 010305 fluids & plasmas, law.invention, ECR heating, Divertor, DENSITY LIMIT, law, Data_FILES, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), 004 Datenverarbeitung, Informatik, Physics, Glow discharge, Condensed Matter Physics, Content (measure theory), ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Electron temperature, Atomic physics, ddc:620, Stellarator, Impurities, Nuclear and High Energy Physics, Technology and Engineering, plasma performance, chemistry.chemical_element, Atmospheric-pressure plasma, PHYSICS, stellarator, Physics::Plasma Physics, NBI heating, 0103 physical sciences, divertor, 010306 general physics, Helium, Plasma performance, turbulence, Física, W7-X, Turbulence, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, chemistry, ddc:004, ddc:600, Energy (signal processing), SYSTEM
Abstract: The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor radius , and plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of with central electron temperatures were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to were reached with hydrogen pellet injection and helium gas fueling. Here, the ions are indirectly heated, and at a central density of a temperature of with was transiently accomplished, which corresponds to with a peak diamagnetic energy of and volume-averaged normalized plasma pressure . The routine access to high plasma densities was opened with boronization of the first wall. After boronization, the oxygen impurity content was reduced by a factor of 10, the carbon impurity content by a factor of 5. The reduced (edge) plasma radiation level gives routinely access to higher densities without radiation collapse, e.g. well above line integrated density and central temperatures at moderate ECRH power. Both X2 and O2 mode ECRH schemes were successfully applied. Core turbulence was measured with a phase contrast imaging diagnostic and suppression of turbulence during pellet injection was observed.
Published: 2019

46. Cracks avoidance with a modified solid tungsten divertor in ASDEX Upgrade

Author: M. Balden, H. Greuner, R. Neu, S. Vorbrugg, M. Li, V. Rohde, N. Jaksic, A. Herrmann, A. Kallenbach, G. Matern, I. Zammuto, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society
Subjects: Materials science, Mechanical Engineering, Nuclear engineering, Divertor, chemistry.chemical_element, Tungsten, 01 natural sciences, Finite element method, 010305 fluids & plasmas, Nuclear Energy and Engineering, chemistry, ASDEX Upgrade, visual_art, 0103 physical sciences, visual_art.visual_art_medium, General Materials Science, Tile, 010306 general physics, Plasma-facing material, Civil and Structural Engineering
Abstract: To clarify the suitability of solid tungsten as plasma facing material, a new divertor, DIV-III, entered in operation in ASDEX Upgrade (AUG) in 2014. Since the first experimental campaign, AUG divertor tiles faced crack issues. Trying to identify the reasoning, a new set of tiles was installed in 2016: many precautions were taken to reduce the stresses possibly causing the cracks. The AUG campaign 2017 started in March and the first results were collected during the short summer opening in 2017. This paper reports on the modification of the tile setup, based on Finite Element Modelling, and on the progress achieved in the first operation phase.
Published: 2018

47. Combined high fluence and high cycle number transient loading of ITER-like monoblocks in Magnum-PSI

Author: Y. Li, M. Balden, S. Brezinsek, Thomas Morgan, G. De Temmerman, and Science and Technology of Nuclear Fusion
Subjects: 010302 applied physics, Nuclear and High Energy Physics, Materials science, Divertor, chemistry.chemical_element, Plasma, Tungsten, Condensed Matter Physics, Microstructure, 01 natural sciences, Fluence, 010305 fluids & plasmas, chemistry, Heat flux, 13. Climate action, 0103 physical sciences, Surface roughness, Seeding, Composite material
Abstract: It is highly desirable to understand the long term evolution of the divertor material under the extreme steady-state and transient heat and particle loads expected during ITER operation. Here the impact of ELM-like transient loading under combined high-flux plasma and transient ELM-like heat loading in Magnum-PSI was explored to determine how plasma affects the fatigue cracking threshold of tungsten due to ELMs. Mock-ups consisting of five ITER-like monoblocks in a chain were simultaneously exposed to high flux plasma and a high power pulsed laser which closely simulated the ELM impact in terms of heat flux and duration. Loading conditions were chosen to enable comparison to existing data from electron-beam loading, while the influence of surface base temperature (750 °C, 1150 °C or 1500 °C) and impurity seeding (addition of 6.5 ion% He+ and/or 8 ion% Ne+) were also investigated. The plasma loading leads to differences in surface morphology and indicates synergistic effects on the extent of the surface damage. Base temperatures at or above 1150 °C are found to lead to a significant reduction in the fatigue cracking threshold by a factor of two or more compared to at 750 °C. Cracked surfaces are found to be more than ten times rougher than the original microstructure, and additionally when seeding impurities are added surface roughness can be significantly increased by up closely factor of two compared to roughening using pure H plasma. Overall the results indicate that avoiding fatigue cracking in ITER will be very challenging, and that understanding the level to which this can therefore be tolerated is vital for anticipating divertor lifetime and reliability.
Published: 2021

48. A hot steam leak during baking of ASDEX Upgrade – Consequences and lessons learned

Author: S. Vorbrugg, A. Herrmann, D. Bösser, K. Hegele, T. Vierle, V. Rohde, G. Schall, J. Stober, M. Balden, K. Hunger, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society
Subjects: Leak, Tokamak, Mechanical Engineering, Nuclear engineering, Water cooled, food and beverages, 01 natural sciences, 010305 fluids & plasmas, law.invention, Nuclear Energy and Engineering, ASDEX Upgrade, law, 0103 physical sciences, Boron containing, Water cooling, Environmental science, General Materials Science, 010306 general physics, Shut down, Civil and Structural Engineering
Abstract: ASDEX Upgrade is a midsize tokamak operated since 1991. A scheduled maintenance and enhancement shut down is done about once a year. After pump down and leak search a baking procedure is started to condition the vacuum vessel for plasma operation. During operation the vacuum vessel and all in-vessel components are water cooled. This cooling system is also used for baking with hot water at 150 °C. During one of these regular baking periods a hot steam leak appears in November 2017. The detection of the leak has triggered a controlled cool down scenario. Nevertheless, between the appearance of the leak and the identification and closing about 100 L water escaped during the controlled cool down from 150 °C to 65 °C into the torus. A fraction of the hot water was distributed as steam all over the torus and condensed at the coldest parts of the vessel, preferentially in remote ports. In addition, the steam interacts with boron containing layers. The resulting acid steam caused additional erosion. The paper presents details of damages, actions taken to remove them as well as measures taken to avoid a future steam leak.
Published: 2021

49. Influence of surface roughness on the sputter yield of Mo under keV D ion irradiation

Author: Antti Hakola, Mitja Kelemen, Matteo Passoni, F. Romeo, P. Pelicon, Andreas Mutzke, M. Pedroni, M. Balden, Espedito Vassallo, Thomas Schwarz-Selinger, David Dellasega, Sabina Markelj, and Rok Zaplotnik
Subjects: Nuclear and High Energy Physics, Materials science, Yield (engineering), Ion beam, Analytical chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, Ion gun, Deuterium, 01 natural sciences, 010305 fluids & plasmas, Pulsed laser deposition, Angular dependence, Surface roughness, Nuclear Energy and Engineering, Sputtering, 0103 physical sciences, General Materials Science, Irradiation, Sputter yield, Thin film, 0210 nano-technology, RBS
Abstract: In this work the influence of surface roughness on the sputter yield of Mo under keV D ion bombardment was investigated for different impact angles. For this purpose, thin films of Mo (~ 120 nm) were deposited by pulsed laser deposition onto graphite substrates with varying surface roughness (Ra ranging from 5 nm to 2–3 µm). The as-deposited samples were irradiated at room temperature by 3 keV D3+ ions originating from an electron-cyclotron-resonance ion gun. Samples were exposed to D ions at angles between 0° and 70° and fluences in range of 1023 D/m2. The areal densities of the Mo marker layers were determined with Rutherford backscattering spectroscopy. For all the surfaces we observed a strong angular dependence of the sputter yield. For smooth and intermediate surface roughnesses, up to Ra ~ 280 nm, we obtained an increase of the sputter yield with the angle up to a factor of five compared to 0°. In contrast, at the highest surface roughness in the 2–3 µm range the sputtering yield decreases with increasing impact angle. The obtained data were compared to SDTrimSP-3D simulations. We obtained good agreement between the simulated and experimental sputter yield for surfaces for which we could provide high resolution atomic force microscopy (AFM) surface representations. As high-resolution surface mapping was not possible for surface roughness of 2–3 μm, we found large deviation between the calculation and the measured data. The combination of measured and simulated data represent important input for predicting the erosion rates of surfaces at inner walls of thermonuclear fusion devices, which are expected to change surface roughness over time by sustained plasma exposure.
Published: 2021

50. Gross and net erosion balance of plasma-facing materials in full-W tokamaks

Author: A. Hakola, J. Likonen, A. Lahtinen, T. Vuoriheimo, M. Groth, H. Kumpulainen, M. Balden, K. Krieger, M. Mayer, T. Schwarz-Selinger, S. Brezinsek, M. Kelemen, S. Markelj, M. Barac, S. Gouasmia, I. Bogdanovic Radovic, A. Uccello, E. Vassallo, D. Dellasega, M. Passoni, M. Sala, E. Bernard, M. Diez, C. Guillemaut, E. Tsitrone, null the ASDEX Upgrade Team, null the EUROfusion MST1 Team, null the EUROfusion WP PFC Contributors, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, EUROfusion MST1 Team, EUROfusion WP PFC Contributors, VTT Technical Research Centre of Finland, University of Helsinki, Fusion and Plasma Physics, Department of Applied Physics, Max Planck Institute for Plasma Physics, Research Center Julich, Jozef Stefan Institute, Rudjer Boskovic Institute, Consiglio Nazionale delle Ricerche (CNR), Polytechnic University of Milan, EURATOM/CEA, Aalto-yliopisto, Aalto University, Department of Physics, and Materials Physics
Subjects: Nuclear and High Energy Physics, Tokamak, WEST, erosion, tungsten, plasma-facing materia, ASDEX Upgrade, Nuclear engineering, chemistry.chemical_element, 114 Physical sciences, 01 natural sciences, 010305 fluids & plasmas, law.invention, CARBON, ASDEX upgrade, law, 0103 physical sciences, 010306 general physics, Plasma-facing material, plasma-facing material, Physics, Divertor, Plasma, Condensed Matter Physics, Balance (accounting), chemistry, Erosion, Environmental science, DIVERTOR, ddc:620, ERO, Carbon
Abstract: openaire: EC/H2020/633053/EU//EUROfusion Gross and net erosion of tungsten (W) and other plasma-facing materials in the divertor region have been investigated in deuterium (D) and helium (He) plasmas during dedicated experiments in L- and H-mode on ASDEX Upgrade and after full-length experimental campaigns on the WEST tokamak. Net erosion was determined via post-exposure analyses of plasma-exposed samples and full-size wall components, and we conclude that the same approach is applicable to gross erosion if marker structures with sub-millimeter dimensions are used to eliminate the contribution of prompt re-deposition. In H-mode plasmas, gross erosion during ELMs may exceed the situation in inter-ELM conditions by 1-2 orders of magnitude while net erosion is typically higher by a factor of 2-3. The largest impact on net erosion is attributed to the electron temperature while the role of the impurity mixtures is weaker, even though both on ASDEX Upgrade and WEST significant amounts of impurities are present in the edge plasmas. Impurities, on the other hand, will lead to the formation of thick co-deposited layers. We have also noted that with increasing surface roughness, net erosion is strongly suppressed and the growth of co-deposited layers is enhanced. In He plasmas, gross erosion is increased compared to D due to the higher mass and charge states of the plasma particles, resulting from larger energies due to sheath acceleration, but strong impurity fluxes can result in apparent net deposition in the divertor. Our results from ASDEX Upgrade and WEST are comparable and indicate typical net-erosion rates of 0.1-0.4 nm s(-1), excluding the immediate vicinity of the strike-point regions.
Published: 2021

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