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1. 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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2. Comparative H-mode density limit studies in JET and AUG

Author

A. Huber, M. Bernert, S. Brezinsek, A.V. Chankin, G. Sergienko, V. Huber, S. Wiesen, P. Abreu, M.N.A. Beurskens, A. Boboc, M. Brix, G. Calabrò, D. Carralero, E. Delabie, T. Eich, H.G. Esser, M. Groth, C. Guillemaut, S. Jachmich, A. Järvinen, E. Joffrin, A. Kallenbach, U. Kruezi, P. Lang, Ch. Linsmeier, C.G. Lowry, C.F. Maggi, G.F. Matthews, A.G. Meigs, Ph. Mertens, F. Reimold, J. Schweinzer, G. Sips, M. Stamp, E. Viezzer, M. Wischmeier, and H. Zohm

Subjects
Nuclear engineering. Atomic power, TK9001-9401
Abstract

Identification of the mechanisms for the H-mode density limit in machines with fully metallic walls, and their scaling to future devices is essential to find for these machines the optimal operational boundaries with the highest attainable density and confinement. Systematic investigations of H-mode density limit plasmas in experiments with deuterium external gas fuelling have been performed on machines with fully metallic walls, JET and AUG and results have been compared with one another.Basically, the operation phases are identical for both tokamaks: the stable H-mode phase, degrading H-mode phase, breakdown of the H-mode with energy confinement deterioration usually accompanied by a dithering cycling phase, followed by the l-mode phase. The observed H-mode density limit on both machines is found close to the Greenwald limit (n/nGW=0.8–1.1 in the observed magnetic configurations). The similar behavior of the radiation on both tokamaks demonstrates that the density limit (DL) is neither related to additional energy losses from the confined region by radiation, nor to an inward collapse of the hot discharge core induced by overcooling of the plasma periphery by radiation.It was observed on both machines that detachment, as well as the X-point MARFE itself, does not trigger a transition in the confinement regime and thus does not present a limit on the plasma density. It is the plasma confinement, most likely determined by edge parameters, which is ultimately responsible for the transition from H- to l-mode.The measured Greenwald fractions are found to be consistent with the predictions from different theoretical models [16,30] based on MHD instability theory in the near-SOL. Keywords: Density limit, H-mode, Detachment, Greenwald fraction, JET, ASDEX Upgrade

Published
2017
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3. 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
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4. The upgraded ASDEX Upgrade contribution to the ITPA confinement database: description and analysis

Author

F. Ryter, C. Angioni, G. Tardini, G. Birkenmeier, P. David, M. Dunne, R. Fischer, T. Pütterich, J. Schweinzer, J. Stober, The ASDEX Upgrade Team, The EUROfusion MST1 Team, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Nuclear and High Energy Physics, Materials science, ASDEX Upgrade, Nuclear engineering, 0103 physical sciences, ITPA, 010306 general physics, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas
Abstract

The ITPA multi-machine confinement database has been recently extended, in particular to account for the effect of the metallic plasma facing components installed in the ASDEX Upgrade and JET tokamaks during the last decade. Confinement data from the ASDEX Upgrade tokamak have been contributed to the ITPA confinement database since 1994. The present version, which includes data from 1994 to 2017, is described and discussed in this article. The aim of this work is to document the database before it is made public and report on the main results on the confinement properties reflected in this database. Through the transition from carbon to metallic wall, the operation at low density originally accessible with the carbon wall, has been strongly limited by the occurrence of tungsten accumulation. However, at medium and high densities, the confinement properties with the carbon and metallic walls are rather similar. The database analysis yields in both cases a rather strong plasma current dependence and a clearly negative magnetic field dependence. The density dependence is negligible, while the well-known positive impact of triangularity appears very clearly. These dependences are partly at variance with the widely-used IPB98(y,2) confinement scaling, but in agreement with the analysis of the upgraded ITPA multi-machine and JET databases. The confinement degradation observed at high density with strong gas puffing can be clearly attributed to the density profile in the outer plasma region, as reported in previous studies.

Published
2021
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5. OVERVIEW OF PHYSICS STUDIES ON ASDEX UPGRADE

Author

Neville C. Luhmann, J. Mailloux, A. Kappatou, Yann Camenen, R. Arredondo Parra, P. Petersson, G. F. Harrer, I. Gomez Ortiz, E. Giovannozzi, S. S. Henderson, C. Sommariva, Thomas Schwarz-Selinger, G. Fuchert, Christopher G. Albert, P. Piovesan, A. Herrmann, C. Piron, Robert Lunsford, J. Hobirk, F. Clairet, L. Xiang, Carlo Cazzaniga, A. Burckhart, B. Kurzan, Bernhard Ploeckl, G. Kocsis, A. Mancini, Benoit Labit, M. Reich, N. den Harder, Faa Federico Felici, M. Oberparleiter, Tamás Szepesi, Sibylle Günter, K. Behler, R. Merkel, Ocleto D'Arcangelo, G. Haas, Alessandro Bortolon, T. B. Cote, E. Trier, P. Simon, A. Gude, Daniele Milanesio, Winfried Kernbichler, Dorothea Gradic, M. Rodriguez-Ramos, G.A. Rattá, G. Croci, O. Tudisco, E. Heyn, M. Groth, J. Gonzalez Martin, Olivier Sauter, Irena Ivanova-Stanik, Massimo Nocente, J. R. Harrison, Martin Heyn, C. Bruhn, C. Ham, L. Shao, M. Schubert, F. Brochard, Yu Gao, Bernd Heinemann, Sandra C. Chapman, Armin Manhard, S. S. Denk, A. Jardin, D. P. Coster, G. Schall, L. Horvath, Alexander Creely, Roman Schrittwieser, Patrick J. McCarthy, C. Castaldo, B. Wiringer, M. J. Mantsinen, Till Höschen, Ph. Lauber, V. Mertens, Anders Nielsen, G. Suarez, M. E. Manso, M. Dibon, S. Wiesen, Mirko Salewski, C. D. Challis, J. Schweinzer, D. Douai, Lorenzo Frassinetti, R. C. Wolf, Mirko Ramisch, P. de Marne, Yueqiang Liu, H. van den Brand, S. Nowak, E. Joffrin, M. Teschke, Karl Schmid, D. Silvagni, L. Giannone, D. I. Refy, E. Wolfrum, M. Sertoli, Chanho Moon, O. J. W. F. Kardaun, A. Ross, S. Elgeti, A. Shalpegin, G. D. Conway, A. Sigalov, Alberto Bottino, Benedikt Geiger, M. Willensdorfer, D. C. van Vugt, Mark Maraschek, W. Zhang, M. Oberkofler, M. Griener, Stylianos Varoutis, Bill Scott, F. Monaco, W. Suttrop, Helmut Faugel, Christian Hopf, J. Vicente, Gerhard Raupp, S. Fietz, Omar Maj, D. Terranova, Q. Yu, E. Seliunin, L. Gil, K. Lackner, I. Novikau, S. Heinzel, G. Birkenmeier, O. Linder, I. Zammuto, H. Fünfgelder, Alessandro Biancalani, D. Prisiazhniuk, Analiza M. Silva, Volker Hauer, Ulrich Stroth, M. Faitsch, Toke Koldborg Jensen, S. Brezinsek, S. Garavaglia, V. Nikolaeva, C. Angioni, T. Maceina, Antti Snicker, O. Schmitz, T. Vierle, A. Scarabosio, D. Carlton, F. Penzel, M. Tardocchi, Riccardo Maggiora, V. Plyusnin, A. Bergmann, A. Bock, G. Rocchi, Andreas Frank Martitsch, J. W. Coenen, I. Erofeev, Pierre Manas, J. Stober, O. Meyer, M. A. Van Zeeland, A. S. Jacobsen, H. Meister, Jens Madsen, E. Smigelskis, A. Lohs, T. Happel, A. Gallo, F. Ryter, P. A. Schneider, A. Kallenbach, Alf Köhn, C. Bottereau, I. Paradela Perez, N. Arden, M. Koubiti, Gergely Papp, Burkhard Plaum, Jorge Ferreira, P. Denner, H. Greuner, Daniel Told, M. Weiland, T. Hayward-Schneider, B. Sieglin, A. Buhler, B. Böswirth, A. Krämer-Flecken, F. Jaulmes, J. Galdon-Quiroga, M. Balden, J. Pinzón Acosta, C. Sozzi, T. Bolzonella, G. Neu, Simon Freethy, T. Sehmer, K. Höfler, T. T. Ribeiro, F. Mink, Ursel Fantz, Q. Yang, Jeppe Olsen, M. Wischmeier, P. Mantica, Timothy Goodman, R. Delogu, T. Tala, Panagiotis Tolias, A. Houben, G. Tardini, A. Kirk, T. Odstrcil, R. Fischer, J. Juul Rasmussen, D. Carralero, H. F. Meyer, P. Martin, J. Miettunen, E. Maljaars, Matthew Carr, Z. Yang, G. Pautasso, B. P. Duval, E. Sytova, Stefano Coda, D. Meshcheriakov, Morten Stejner, S. Zoletnik, Thomas Zehetbauer, M. Li, F. Liu, R. Neu, A. Drenik, P. Manz, E. Fable, Otto Asunta, Zhixin Lu, S. Kálvin, Bruce Lipschultz, Vinodh Bandaru, A. Di Siena, Mattia Siccinio, S. Costea, Frank Jenko, Peter Lang, V. Rohde, Manfred Zilker, F. Nabais, H. J. Sun, Chris Hegna, A. Krivska, M. Rott, S. E. Sharapov, Antoine Merle, J. Bernardo, K. Engelhardt, M. Garcia-Munoz, M. Kantor, M. Hölzl, J. M. Santos, L. Guimarais, A. Figuereido, Carlos B. da Silva, Ch. Day, P. David, U. von Toussaint, T. C. Blanken, D. A. Ryan, F. Palermo, Silvio Ceccuzzi, J.-M. Noterdaeme, M. Gobbin, A. Jansen van Vuuren, C.-P. Kasemann, D. Rittich, Wouter Tierens, Taina Kurki-Suonio, C. Martens, R. Riedl, Antti Hakola, A. Czarnecka, F. Hitzler, M. Spolaore, M. Tripský, D. Brida, A. V. Chankin, Alessandro Pau, T. Ilkei, K. Krieger, Emanuele Poli, Florian Laggner, J. F. Rivero-Rodriguez, Wolfgang Jacob, Nengchao Wang, Anne White, S. Kjer Hansen, Stefan Kragh Nielsen, M. Fröschle, R. Bilato, O. Kudlacek, Tobias Görler, A. Stegmeir, Ari Salmi, L. Colas, A. Mlynek, Istvan Cziegler, V. Bobkov, James Buchanan, A. Gräter, T. Luda di Cortemiglia, R. Drube, John Hammer Holm, Giuliana Sias, K. Galazka, Giuseppe Gorini, V. Igochine, B. Vanovac, O. P. Ford, A. Garcia-Carrasco, R. M. McDermott, B. Tal, A. Lebschy, M. Cavedon, Julia Fuchs, E. Viezzer, R. Dux, R.A. Pitts, Svetlana V. Ratynskaia, Aqsa Shabbir, Sergei Kasilov, M. Bernert, S. Saarelma, Gergö Pokol, F. Reimold, Geert Verdoolaege, M. Mayer, Marek Rubel, L. Sanchis-Sanchez, R. Maingi, William Hornsby, U. Plank, C. Cianfarani, N. Vianello, A. Huber, Gustavo Granucci, Didier Mazon, S. Glöggler, J. Simpson, I. Faust, G. L. Ravera, Laurie Porte, Johann Riesch, F. Janky, A Lyssoivan, T. Pütterich, F. Orain, M. Valisa, B. Esposito, C. Gleason-González, Juha Karhunen, M. Valovic, H. Maier, Gábor Cseh, A. Nemes-Czopf, E. Thoren, O. Pan, T. Eich, R. Coelho, M.R. de Baar, E. Strumberger, T. Hellsten, Lionello Marrelli, Boglarka Erdos, Pascale Hennequin, R. Ochoukov, H. Zohm, D. Wagner, Yevgen O. Kazakov, A. Medvedeva, M. G. Dunne, W. Treutterer, N. Leuthold, R. Zagórski, S. Potzel, V. Klevarova, Dirk Reiser, X. Wang, T. Lunt, Meyer, H, Angioni, C, Albert, C, Arden, N, Arredondo Parra, R, Asunta, O, De Baar, M, Balden, M, Bandaru, V, Behler, K, Bergmann, A, Bernardo, J, Bernert, M, Biancalani, A, Bilato, R, Birkenmeier, G, Blanken, T, Bobkov, V, Bock, A, Bolzonella, T, Bortolon, A, Boswirth, B, Bottereau, C, Bottino, A, Van Den Brand, H, Brezinsek, S, Brida, D, Brochard, F, Bruhn, C, Buchanan, J, Buhler, A, Burckhart, A, Camenen, Y, Carlton, D, Carr, M, Carralero, D, Castaldo, C, Cavedon, M, Cazzaniga, C, Ceccuzzi, S, Challis, C, Chankin, A, Chapman, S, Cianfarani, C, Clairet, F, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, Cote, T, Creely, A, Croci, G, Cseh, G, Czarnecka, A, Cziegler, I, D'Arcangelo, O, David, P, Day, C, Delogu, R, De Marne, P, Denk, S, Denner, P, Dibon, M, Di Siena, A, Douai, D, Drenik, A, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Engelhardt, K, Erdos, B, Erofeev, I, Esposito, B, Fable, E, Faitsch, M, Fantz, U, Faugel, H, Faust, I, Felici, F, Ferreira, J, Fietz, S, Figuereido, A, Fischer, R, Ford, O, Frassinetti, L, Freethy, S, Froschle, M, Fuchert, G, Fuchs, J, Funfgelder, H, Galazka, K, Galdon-Quiroga, J, Gallo, A, Gao, Y, Garavaglia, S, Garcia-Carrasco, A, Garcia-Munoz, M, Geiger, B, Giannone, L, Gil, L, Giovannozzi, E, Gleason-Gonzalez, C, Gloggler, S, Gobbin, M, Gorler, T, Gomez Ortiz, I, Gonzalez Martin, J, Goodman, T, Gorini, G, Gradic, D, Grater, A, Granucci, G, Greuner, H, Griener, M, Groth, M, Gude, A, Gunter, S, Guimarais, L, Haas, G, Hakola, A, Ham, C, Happel, T, Den Harder, N, Harrer, G, Harrison, J, Hauer, V, Hayward-Schneider, T, Hegna, C, Heinemann, B, Heinzel, S, Hellsten, T, Henderson, S, Hennequin, P, Herrmann, A, Heyn, M, Heyn, E, Hitzler, F, Hobirk, J, Hofler, K, Holzl, M, Hoschen, T, Holm, J, Hopf, C, Hornsby, W, Horvath, L, Houben, A, Huber, A, Igochine, V, Ilkei, T, Ivanova-Stanik, I, Jacob, W, Jacobsen, A, Janky, F, Jansen Van Vuuren, A, Jardin, A, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Kasemann, C, Kallenbach, A, Kalvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kasilov, S, Kazakov, Y, Kernbichler, W, Kirk, A, Kjer Hansen, S, Klevarova, V, Kocsis, G, Kohn, A, Koubiti, M, Krieger, K, Krivska, A, Kramer-Flecken, A, Kudlacek, O, Kurki-Suonio, T, Kurzan, B, Labit, B, Lackner, K, Laggner, F, Lang, P, Lauber, P, Lebschy, A, Leuthold, N, Li, M, Linder, O, Lipschultz, B, Liu, F, Liu, Y, Lohs, A, Lu, Z, Luda Di Cortemiglia, T, Luhmann, N, Lunsford, R, Lunt, T, Lyssoivan, A, Maceina, T, Madsen, J, Maggiora, R, Maier, H, Maj, O, Mailloux, J, Maingi, R, Maljaars, E, Manas, P, Mancini, A, Manhard, A, Manso, M, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Martens, C, Martin, P, Marrelli, L, Martitsch, A, Mayer, M, Mazon, D, Mccarthy, P, Mcdermott, R, Meister, H, Medvedeva, A, Merkel, R, Merle, A, Mertens, V, Meshcheriakov, D, Meyer, O, Miettunen, J, Milanesio, D, Mink, F, Mlynek, A, Monaco, F, Moon, C, Nabais, F, Nemes-Czopf, A, Neu, G, Neu, R, Nielsen, A, Nielsen, S, Nikolaeva, V, Nocente, M, Noterdaeme, J, Novikau, I, Nowak, S, Oberkofler, M, Oberparleiter, M, Ochoukov, R, Odstrcil, T, Olsen, J, Orain, F, Palermo, F, Pan, O, Papp, G, Paradela Perez, I, Pau, A, Pautasso, G, Penzel, F, Petersson, P, Pinzon Acosta, J, Piovesan, P, Piron, C, Pitts, R, Plank, U, Plaum, B, Ploeckl, B, Plyusnin, V, Pokol, G, Poli, E, Porte, L, Potzel, S, Prisiazhniuk, D, Putterich, T, Ramisch, M, Rasmussen, J, Ratta, G, Ratynskaia, S, Raupp, G, Ravera, G, Refy, D, Reich, M, Reimold, F, Reiser, D, Ribeiro, T, Riesch, J, Riedl, R, Rittich, D, Rivero-Rodriguez, J, Rocchi, G, Rodriguez-Ramos, M, Rohde, V, Ross, A, Rott, M, Rubel, M, Ryan, D, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Sanchis-Sanchez, L, Santos, J, Sauter, O, Scarabosio, A, Schall, G, Schmid, K, Schmitz, O, Schneider, P, Schrittwieser, R, Schubert, M, Schwarz-Selinger, T, Schweinzer, J, Scott, B, Sehmer, T, Seliunin, E, Sertoli, M, Shabbir, A, Shalpegin, A, Shao, L, Sharapov, S, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Silvagni, D, Simon, P, Simpson, J, Smigelskis, E, Snicker, A, Sommariva, C, Sozzi, C, Spolaore, M, Stegmeir, A, Stejner, M, Stober, J, Stroth, U, Strumberger, E, Suarez, G, Sun, H, Suttrop, W, Sytova, E, Szepesi, T, Tal, B, Tala, T, Tardini, G, Tardocchi, M, Teschke, M, Terranova, D, Tierens, W, Thoren, E, Told, D, Tolias, P, Tudisco, O, Treutterer, W, Trier, E, Tripsky, M, Valisa, M, Valovic, M, Vanovac, B, Van Vugt, D, Varoutis, S, Verdoolaege, G, Vianello, N, Vicente, J, Vierle, T, Viezzer, E, Von Toussaint, U, Wagner, D, Wang, N, Wang, X, Weiland, M, White, A, Wiesen, S, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Xiang, L, Yang, Q, Yang, Z, Yu, Q, Zagorski, R, Zammuto, I, Zhang, W, Van Zeeland, M, Zehetbauer, T, Zilker, M, Zoletnik, S, Zohm, H, Meyer, H., Universidad de Sevilla, Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla. RNM138: Física Nuclear Aplicada, Universidad de Sevilla. TEP111: Ingeniería Mecánica, CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), 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), Culham Science Centre, Max-Planck-Institut für Plasmaphysik, Department of Applied Physics, Dutch Institute for Fundamental Energy Research, University of Lisbon, Eindhoven University of Technology, National Research Council of Italy, Princeton University, CEA, Forschungszentrum Jülich, Université de Lorraine, CNRS, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, University of Warwick, Swiss Federal Institute of Technology Lausanne, University of Innsbruck, University of Wisconsin-Madison, Massachusetts Institute of Technology, Hungarian Academy of Sciences, Soltan Institute for Nuclear Studies, University of York, Karlsruhe Institute of Technology, KTH Royal Institute of Technology, University of Seville, University of Milan - Bicocca, Fusion and Plasma Physics, VTT Technical Research Centre of Finland, Vienna University of Technology, Max-Planck Computing and Data Facility, General Atomics, Université Paris-Saclay, Graz University of Technology, Institut für Grenzflachenverfahrenstechnik und Plasmatechnologie, Danmarks Tekniske Universitet, Budapest University of Technology and Economics, Polish Academy of Sciences, Royal Military Academy, Ghent University, ITER Organization, University of California Davis, Polytechnic University of Turin, Barcelona Supercomputing Center, University College Cork, Chalmers University of Technology, University of Cagliari, ITER, CIEMAT, CAS - Institute of Plasma Physics, Max Planck Institute for Plasma Physics, Aalto-yliopisto, Aalto University, Angioni, C., Albert, C. G., Arden, N., Arredondo Parra, R., Asunta, O., De Baar, M., Balden, M., Bandaru, V., Behler, K., Bergmann, A., Bernardo, J., Bernert, M., Biancalani, A., Bilato, R., Birkenmeier, G., Blanken, T. C., Bobkov, V., Bock, A., Bolzonella, T., Bortolon, A., Boswirth, B., Bottereau, C., Bottino, A., Van Den Brand, H., Brezinsek, S., Brida, D., Brochard, F., Bruhn, C., Buchanan, J., Buhler, A., Burckhart, A., Camenen, Y., Carlton, D., Carr, M., Carralero, D., Castaldo, C., Cavedon, M., Cazzaniga, C., Ceccuzzi, S., Challis, C., Chankin, A., Chapman, S., Cianfarani, C., Clairet, F., Coda, S., Coelho, R., Coenen, J. W., Colas, L., Conway, G. D., Costea, S., Coster, D. P., Cote, T. B., Creely, A., Croci, G., Cseh, G., Czarnecka, A., Cziegler, I., D'Arcangelo, O., David, P., Day, C., Delogu, R., De Marne, P., Denk, S. S., Denner, P., Dibon, M., Di Siena, A., Douai, D., Drenik, A., Drube, R., Dunne, M., Duval, B. P., Dux, R., Eich, T., Elgeti, S., Engelhardt, K., Erdos, B., Erofeev, I., Esposito, B., Fable, E., Faitsch, M., Fantz, U., Faugel, H., Faust, I., Felici, F., Ferreira, J., Fietz, S., Figuereido, A., Fischer, R., Ford, O., Frassinetti, L., Freethy, S., Froschle, M., Fuchert, G., Fuchs, J. C., Funfgelder, H., Galazka, K., Galdon-Quiroga, J., Gallo, A., Gao, Y., Garavaglia, S., Garcia-Carrasco, A., Garcia-Munoz, M., Geiger, B., Giannone, L., Gil, L., Giovannozzi, E., Gleason-Gonzalez, C., Gloggler, S., Gobbin, M., Gorler, T., Gomez Ortiz, I., Gonzalez Martin, J., Goodman, T., Gorini, G., Gradic, D., Grater, A., Granucci, G., Greuner, H., Griener, M., Groth, M., Gude, A., Gunter, S., Guimarais, L., Haas, G., Hakola, A. H., Ham, C., Happel, T., Den Harder, N., Harrer, G. F., Harrison, J., Hauer, V., Hayward-Schneider, T., Hegna, C. C., Heinemann, B., Heinzel, S., Hellsten, T., Henderson, S., Hennequin, P., Herrmann, A., Heyn, M. F., Heyn, E., Hitzler, F., Hobirk, J., Hofler, K., Holzl, M., Hoschen, T., Holm, J. H., Hopf, C., Hornsby, W. A., Horvath, L., Houben, A., Huber, A., Igochine, V., Ilkei, T., Ivanova-Stanik, I., Jacob, W., Jacobsen, A. S., Janky, F., Jansen Van Vuuren, A., Jardin, A., Jaulmes, F., Jenko, F., Jensen, T., Joffrin, E., Kasemann, C. -P., Kallenbach, A., Kalvin, S., Kantor, M., Kappatou, A., Kardaun, O., Karhunen, J., Kasilov, S., Kazakov, Y., Kernbichler, W., Kirk, A., Kjer Hansen, S., Klevarova, V., Kocsis, G., Kohn, A., Koubiti, M., Krieger, K., Krivska, A., Kramer-Flecken, A., Kudlacek, O., Kurki-Suonio, T., Kurzan, B., Labit, B., Lackner, K., Laggner, F., Lang, P. T., Lauber, P., Lebschy, A., Leuthold, N., Li, M., Linder, O., Lipschultz, B., Liu, F., Liu, Y., Lohs, A., Lu, Z., Luda Di Cortemiglia, T., Luhmann, N. C., Lunsford, R., Lunt, T., Lyssoivan, A., Maceina, T., Madsen, J., Maggiora, R., Maier, H., Maj, O., Mailloux, J., Maingi, R., Maljaars, E., Manas, P., Mancini, A., Manhard, A., Manso, M. -E., Mantica, P., Mantsinen, M., Manz, P., Maraschek, M., Martens, C., Martin, P., Marrelli, L., Martitsch, A., Mayer, M., Mazon, D., Mccarthy, P. J., Mcdermott, R., Meister, H., Medvedeva, A., Merkel, R., Merle, A., Mertens, V., Meshcheriakov, D., Meyer, O., Miettunen, J., Milanesio, D., Mink, F., Mlynek, A., Monaco, F., Moon, C., Nabais, F., Nemes-Czopf, A., Neu, G., Neu, R., Nielsen, A. H., Nielsen, S. K., Nikolaeva, V., Nocente, M., Noterdaeme, J. -M., Novikau, I., Nowak, S., Oberkofler, M., Oberparleiter, M., Ochoukov, R., Odstrcil, T., Olsen, J., Orain, F., Palermo, F., Pan, O., Papp, G., Paradela Perez, I., Pau, A., Pautasso, G., Penzel, F., Petersson, P., Pinzon Acosta, J., Piovesan, P., Piron, C., Pitts, R., Plank, U., Plaum, B., Ploeckl, B., Plyusnin, V., Pokol, G., Poli, E., Porte, L., Potzel, S., Prisiazhniuk, D., Putterich, T., Ramisch, M., Rasmussen, J., Ratta, G. A., Ratynskaia, S., Raupp, G., Ravera, G. L., Refy, D., Reich, M., Reimold, F., Reiser, D., Ribeiro, T., Riesch, J., Riedl, R., Rittich, D., Rivero-Rodriguez, J. F., Rocchi, G., Rodriguez-Ramos, M., Rohde, V., Ross, A., Rott, M., Rubel, M., Ryan, D., Ryter, F., Saarelma, S., Salewski, M., Salmi, A., Sanchis-Sanchez, L., Santos, J., Sauter, O., Scarabosio, A., Schall, G., Schmid, K., Schmitz, O., Schneider, P. A., Schrittwieser, R., Schubert, M., Schwarz-Selinger, T., Schweinzer, J., Scott, B., Sehmer, T., Seliunin, E., Sertoli, M., Shabbir, A., Shalpegin, A., Shao, L., Sharapov, S., Sias, G., Siccinio, M., Sieglin, B., Sigalov, A., Silva, A., Silva, C., Silvagni, D., Simon, P., Simpson, J., Smigelskis, E., Snicker, A., Sommariva, C., Sozzi, C., Spolaore, M., Stegmeir, A., Stejner, M., Stober, J., Stroth, U., Strumberger, E., Suarez, G., Sun, H. -J., Suttrop, W., Sytova, E., Szepesi, T., Tal, B., Tala, T., Tardini, G., Tardocchi, M., Teschke, M., Terranova, D., Tierens, W., Thoren, E., Told, D., Tolias, P., Tudisco, O., Treutterer, W., Trier, E., Tripsky, M., Valisa, M., Valovic, M., Vanovac, B., Van Vugt, D., Varoutis, S., Verdoolaege, G., Vianello, N., Vicente, J., Vierle, T., Viezzer, E., Von Toussaint, U., Wagner, D., Wang, N., Wang, X., Weiland, M., White, A. E., Wiesen, S., Willensdorfer, M., Wiringer, B., Wischmeier, M., Wolf, R., Wolfrum, E., Xiang, L., Yang, Q., Yang, Z., Yu, Q., Zagorski, R., Zammuto, I., Zhang, W., Van Zeeland, M., Zehetbauer, T., Zilker, M., Zoletnik, S., Zohm, H., ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Magnetic confinement, Edge-localized modes (ELMs), Nuclear engineering, PLASMAS, Nuclear physics, 01 natural sciences, 010305 fluids & plasmas, ASDEX Upgrade, ITER, MODE, Physics, iter, Divertor, magnetic confinement, Magnetic confinement fusion, mode, Dissipation, Condensed Matter Physics, ddc, Tokamak physics, Física nuclear, tokamak physics, Tokamaks, FLUX, Nuclear and High Energy Physics, Technology and Engineering, DEMO, nuclear fusion, Electron cyclotron resonance, Resonant magnetic perturbations, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, ddc:530, 010306 general physics, SOLID TUNGSTEN DIVERTOR, Física [Àrees temàtiques de la UPC], demo, plasmas, solid tungsten divertor, flux, ___, HEAVY ALLOYS, Magnetohydrodynamics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], heavy alloys
Abstract

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m−1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and Er allow for inter ELM transport analysis confirming that Er is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle—measured for the first time—or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO. 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. "Article signat per més de 100 autors/es: H. Meyer, for the AUG Team: D. Aguiam, C. Angioni, C.G. Albert, N. Arden, R. Arredondo Parra, O. Asunta, M. de Baar, M. Balden, V. Bandaru, K. Behler, A. Bergmann, J. Bernardo, M. Bernert, A. Biancalani, R. Bilato, G. Birkenmeier, T.C. Blanken, V. Bobkov, A. Bock, T. Bolzonella, A. Bortolon, B. Böswirth, C. Bottereau, A. Bottino, H. van den Brand, S. Brezinsek, D. Brida, F. Brochard, C. Bruhn, J. Buchanan, A. Buhler, A. Burckhart, Y. Camenen, D. Carlton, M. Carr, D. Carralero, C. Castaldo, M. Cavedon, C. Cazzaniga, S. Ceccuzzi, C. Challis, A. Chankin, S. Chapman, C. Cianfarani, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, L. Colas, G.D. Conway, S. Costea, D.P. Coster, T.B. Cote, A. Creely, G. Croci, G. Cseh, A. Czarnecka, I. Cziegler, O. D'Arcangelo, P. David, C. Day, R. Delogu, P. de Marné, S.S. Denk, P. Denner, M. Dibon, A. Di Siena, D. Douai, A. Drenik, R. Drube, M. Dunne, B.P. Duval, R. Dux, T. Eich, S. Elgeti, K. Engelhardt, B. Erdös, I. Erofeev, B. Esposito, E. Fable, M. Faitsch, U. Fantz, H. Faugel, I. Faust, F. Felici, J. Ferreira, S. Fietz, A. Figuereido, R. Fischer, O. Ford, L. Frassinetti, S. Freethy, M. Fröschle, G. Fuchert, J.C. Fuchs, H. Fünfgelder, K. Galazka, J. Galdon-Quiroga, A. Gallo, Y. Gao, S. Garavaglia, A. Garcia-Carrasco, M. Garcia-Muñoz, B. Geiger, L. Giannone, L. Gil, E. Giovannozzi, C. Gleason-González, S. Glöggler, M. Gobbin, T. Görler, I. Gomez Ortiz, J. Gonzalez Martin, T. Goodman, G. Gorini, D. Gradic, A. Gräter, G. Granucci, H. Greuner, M. Griener, M. Groth, A. Gude, S. Günter, L. Guimarais, G. Haas, A.H. Hakola, C. Ham, T. Happel, N. den Harder, G.F. Harrer, J. Harrison, V. Hauer, T. Hayward-Schneider, C.C. Hegna, B. Heinemann, S. Heinzel, T. Hellsten, S. Henderson, P. Hennequin, A. Herrmann, M.F. Heyn, E. Heyn, F. Hitzler, J. Hobirk, K. Höfler, M. Hölzl, T. Höschen, J.H. Holm, C. Hopf, W.A. Hornsby, L. Horvath, A. Houben, A. Huber, V. Igochine, T. Ilkei, I. Ivanova-Stanik, W. Jacob, A.S. Jacobsen, F. Janky, A. Jansen van Vuuren, A. Jardin, F. Jaulmes, F. Jenko, T. Jensen, E. Joffrin, C.-P. Käsemann, A. Kallenbach, S. Kálvin, M. Kantor, A. Kappatou, O. Kardaun, J. Karhunen, S. Kasilov,, Y. Kazakov, W. Kernbichler, A. Kirk, S. Kjer Hansen, V. Klevarova, G. Kocsis, A. Köhn, M. Koubiti, K. Krieger, A. Krivska, A. Krämer-Flecken, O. Kudlacek, T. Kurki-Suonio, B. Kurzan, B. Labit, K. Lackner, F. Laggner, P.T. Lang, P. Lauber, A. Lebschy, N. Leuthold, M. Li, O. Linder, B. Lipschultz, F. Liu, Y. Liu, A. Lohs, Z. Lu, T. Luda di Cortemiglia, N.C. Luhmann, R. Lunsford, T. Lunt, A. Lyssoivan, T. Maceina, J. Madsen, R. Maggiora, H. Maier, O. Maj, J. Mailloux, R. Maingi, E. Maljaars, P. Manas, A. Mancini, A. Manhard, M.-E. Manso, P. Mantica, M. Mantsinen, P. Manz, M. Maraschek, C. Martens, P. Martin, L. Marrelli, A. Martitsch, M. Mayer, D. Mazon, P.J. McCarthy, R. McDermott, H. Meister, A. Medvedeva, R. Merkel, A. Merle, V. Mertens, D. Meshcheriakov, O. Meyer, J. Miettunen, D. Milanesio, F. Mink, A. Mlynek, F. Monaco, C. Moon, F. Nabais, A. Nemes-Czopf, G. Neu, R. Neu, A.H. Nielsen, S.K. Nielsen, V. Nikolaeva, M. Nocente, J.-M. Noterdaeme, I. Novikau, S. Nowak, M. Oberkofler, M. Oberparleiter, R. Ochoukov, T. Odstrcil, J. Olsen, F. Orain, F. Palermo, O. Pan, G. Papp, I. Paradela Perez, A. Pau, G. Pautasso, F. Penzel, P. Petersson, J. Pinzón Acosta, P. Piovesan, C. Piron, R. Pitts, U. Plank, B. Plaum, B. Ploeckl, V. Plyusnin, G. Pokol, E. Poli, L. Porte, S. Potzel, D. Prisiazhniuk, T. Pütterich, M. Ramisch, J. Rasmussen, G.A. Rattá, S. Ratynskaia, G. Raupp, G.L. Ravera, D. Réfy, M. Reich, F. Reimold, D. Reiser, T. Ribeiro, J. Riesch, R. Riedl, D. Rittich, J.F. Rivero-Rodriguez, G. Rocchi, M. Rodriguez-Ramos, V. Rohde, A. Ross1, M. Rott, M. Rubel, D. Ryan, F. Ryter, S. Saarelma, M. Salewski, A. Salmi, L. Sanchis-Sanchez, J. Santos, O. Sauter, A. Scarabosio, G. Schall, K. Schmid, O. Schmitz, P.A. Schneider, R. Schrittwieser, M. Schubert, T. Schwarz-Selinger, J. Schweinzer, B. Scott, T. Semer, E. Seliunin, M. Sertoli, A. Shabbir, A. Shalpegin, L. Shao, S. Sharapov, G. Sias, M. Siccinio, B. Sieglin, A. Sigalov, A. Silva, C. Silva, D. Silvagni, P. Simon, J. Simpson, E. Smigelskis, A. Snicker, C. Sommariva, C. Sozzi, M. Spolaore, A. Stegmeir, M. Stejner, J. Stober, U. Stroth, E. Strumberger, G. Suarez, H.-J. Sun, W. Suttrop, E. Sytova, T. Szepesi, B. Tál, T. Tala, G. Tardini, M. Tardocchi, M. Teschke, D. Terranova, W. Tierens, E. Thorén, D. Told, P. Tolias, O. Tudisco, W. Treutterer, E. Trier, M. Tripský, M. Valisa, M. Valovic, B. Vanovac, D. van Vugt, S. Varoutis, G. Verdoolaege, N. Vianello, J. Vicente, T. Vierle, E. Viezzer, U. von Toussaint, D. Wagner, N. Wang, X. Wang, M. Weiland, A.E. White, S. Wiesen, M. Willensdorfer, B. Wiringer, M. Wischmeier, R. Wolf, E. Wolfrum, L. Xiang, Q. Yang, Z. Yang, Q. Yu, R. Zagórski, I. Zammuto, W. Zhang, M. van Zeeland, T. Zehetbauer, M. Zilker, S. Zoletnik, H. Zohm and the EUROfusion MST1 Team55

Published
2018
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6. Assessment of the baseline scenario at q95~3 for ITER

Author

Hajime Urano, Francesca Turco, P. de Vries, Itpa-Ios Tg members, S.H. Kim, J. Stober, I. Nunes, E. Joffrin, T. C. Luce, T. Pütterich, Shunsuke Ide, J. Schweinzer, C.E. Kessel, F.G. Rimini, W. M. Solomon, P. J. Lomas, A. C. C. Sips, J. Hobirk, Jet Contributors, S.M. Wolfe, Experts, JET Contributors, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, DIII-D Team, C-Mod Team, JT-U Team, and ITPA-IOS TG Members and Experts

Subjects
Nuclear and High Energy Physics, Tokamak, law, Nuclear engineering, 0103 physical sciences, 010306 general physics, Condensed Matter Physics, Baseline (configuration management), 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention
Abstract

The International Tokamak Physics Activity topical group on integrated operational scenarios has compiled a database of stationary H-mode discharges at q(95) similar to 3 from AUG, C-Mod, DIII-D, J ...

Published
2018

7. The role of carbon and nitrogen on the H-mode confinement in ASDEX Upgrade with a metal wall

Author

E. Wolfrum, R. Fischer, M. N. A. Beurskens, A. Kallenbach, E. Viezzer, Florian Laggner, J. Schweinzer, G. Tardini, Lorenzo Frassinetti, M. Bernert, Aaro Järvinen, M. G. Dunne, S. Potzel, R. M. McDermott, M. Cavedon, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, EUROfusion MST1 Team, Beurskens, M, Dunne, M, Frassinetti, L, Bernert, M, Cavedon, M, Fischer, R, Jarvinen, A, Kallenbach, A, Laggner, F, Mcdermott, R, Potzel, S, Schweinzer, J, Tardini, G, Viezzer, E, and Wolfrum, E

Subjects
Nuclear and High Energy Physics, Electron density, Materials science, tungsten, metal wall, chemistry.chemical_element, Tungsten, 01 natural sciences, nitrogen, 010305 fluids & plasmas, Pedestal, ASDEX Upgrade, 0103 physical sciences, 010306 general physics, Divertor, carbon, Plasma, Condensed Matter Physics, impurity seeding, Nitrogen, radiation, chemistry, confinement, Atomic physics, Carbon
Abstract

Carbon (CD4) and nitrogen (N2) have been seeded in ASDEX Upgrade (AUG) with a tungsten wall and have both led to a 20–30% confinement improvement. The reference plasma is a standard target plasma with I p /B T = 1 MA/2.5 T, total input power P tot ~ 12 MW and normalized pressure of β N ~ 1.8. Carbon and nitrogen are almost perfectly exchangeable for the core, pedestal and divertor plasma in this experiment where impurity concentrations of C and N of 2% are achieved and Z eff only mildly increases from ~1.3 to ~1.7. As the radiation potentials of C and N are similar and peak well below 100 eV, both impurities act as divertor radiators and radiate well outside the pedestal region. The outer divertor is purposely kept in an attached state when C and N are seeded to avoid confinement degradation by detachment. As reported in earlier publications for nitrogen, carbon is also seen to reduce the high field side high density (the so-called HFSHD) in the scrape off layer above the inner divertor strike point by about 50%. This is accompanied by a confinement improvement for both low (δ ~ 0.25) and high (δ ~ 0.4) triangularity configurations for both seeding gases, due to an increase of pedestal temperature and stiff core temperature profiles. The electron density profiles show no apparent change due to the seeding. As an orthogonal effect, increasing the triangularity leads to an additionally increased pedestal density, independent of the impurity seeding. This experiment further closes the gap in understanding the confinement differences observed in carbon and metal wall devices; the absence of carbon can be substituted by nitrogen which leads to a similar confinement benefit. So far, no definite physics explanation for the confinement enhancement has been obtained, but the experimental observations in this paper provide input for further model development.

Published
2016
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8. The ASDEX Upgrade Program Targeting Gaps to Fusion Energy

Author

Jean-Marie Noterdaeme, A. Kallenbach, M. Reich, Rudolf Neu, Albrecht Herrmann, W. Suttrop, M. Bernert, A. Kirk, J. Schweinzer, M. N. A. Beurskens, A. Bock, Peter Lang, G. Pautasso, J. Stober, H. Zohm, and V. Bobkov

Subjects
Nuclear and High Energy Physics, Tokamak, Materials science, Nuclear engineering, Divertor, Cyclotron, Cryopump, Fusion power, Collisionality, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Electron cyclotron resonance, 010305 fluids & plasmas, law.invention, ASDEX Upgrade, law, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

Recent experiments in ASDEX Upgrade aimed at improving the physics base for ITER and DEMO to prepare operation and aid the design. In order to increase its exhaust capabilities and operational flexibility, a new bulk W divertor as well as an adjustable cryopump had been installed prior to the 2014 campaign. In experiments with high-field-side pellet injection, central electron densities twice as high as the Greenwald density limit could be achieved without strongly increasing the pedestal density and deleterious effect on confinement. Due to its large installed heating power, a large normalized heat flux $P_{\mathrm{ sep}}/R = 10$ MWm $^{-1}$ has been reached, representing two-thirds of the ITER value, under partially detached conditions with a peak target heat flux well below 10 MWm $^{-2}$ . The divertor load could be further reduced by increasing the core radiation, still keeping the confinement in the range of $H_{98y2}\approx 1$ . Suppression of edge-localized modes (ELMs) at low collisionality has been observed in a narrow spectral window in contrast to earlier results at high densities. The ITER $Q = 10$ baseline scenario has been investigated, matching as close as possible the triangularity, the plasma beta, $q_{95}$ , and the distance to the L-H threshold. It turned out that the ELM frequency is low and consequently the energy ejected by a single ELM is very high and ELM mitigation appears to be difficult. As a possible alternative, a scenario has been developed achieving a similar performance at a lower plasma current (and consequently higher $q_{95})$ . Experiments using electron cyclotron current drive (ECCD) with feedback-controlled deposition have allowed successfully testing several control strategies for ITER, including automated control of (3, 2) and (2, 1) neoclassical tearing modes during a single discharge. Concerning advanced scenarios, experiments with central ctr-ECCD have been performed in order to modify the q-profile. A strong reversal of the q-profile could be stationarily achieved and an internal transport barrier could be triggered. In disruption mitigation studies with massive gas injection (MGI), a runaway electron beam could be provoked and mitigated by a second MGI. Ongoing enhancements aim at strengthening the power supplies in order to allow full use of the installed heating power, the exchange of two ion cyclotron resonance heating (ICRH) antennas to reduce the W influx during ICRH, and the upgrading of the electron cyclotron resonance heating (ECRH) system to 7–8 MW for 10 s.

Published
2016

9. Development of the Q = 10 scenario for ITER on ASDEX Upgrade (AUG)

Author

E. Joffrin, F. Ryter, R. Fischer, E. Wolfrum, V. Bobkov, M. N. A. Beurskens, R. Dux, Christian Hopf, Ch. Fuchs, J. Schweinzer, Peter Lang, A. Kallenbach, J. Stober, H. Zohm, G. Tardini, Th. Pütterich, Lorenzo Frassinetti, A. Mlynek, EUROfusion MST1 Team, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Nuclear and High Energy Physics, Heating power, Tokamak, Nuclear engineering, chemistry.chemical_element, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, chemistry, ASDEX Upgrade, law, 0103 physical sciences, 010306 general physics, Helium
Abstract

The development of the baseline H-mode scenario foreseen for ITER on the ASDEX Upgrade tokamak, i.e. discharges at q 95 = 3, relatively low β N ~ 1.8, high normalized density n/n GW ~ 0.85 and high triangularity δ = 0.4, focused on the integration of elements foreseen for ITER and available on ASDEX Upgrade, such as ELM mitigation techniques and impurity seeding in combination with a metallic wall. Values for density and energy confinement simultaneously came close to the requirements of the ITER baseline scenario as long as β N stayed above 2. At lower heating power and thus lower β N normalized energy confinement H 98y2 ~ 0.85 is obtained. It has been found that stationary discharges are not easily achieved under these conditions due to the low natural ELM frequency occurring at the low q 95/high δ operational point. Up until now the ELM parameters were uncontrollable with the tools developed in other scenarios. Therefore studies on an alternative operational point at higher β N and q 95 have been conducted. In order to prepare for the ITER first non-activation operational phase, Helium operation has been investigated as well.

Published
2016
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10. ASDEX Upgrade program for closing gaps to fusion energy

Author

M. Reich, J. M. Noterdaeme, M. Bernert, Rudolf Neu, W. Suttrop, A. Kirk, M. Beurskens, J. Stober, H. Zohm, G. Pautasso, A. Herrmann, A. Bock, J. Schweinzer, A. Kallenbach, and Peter Lang

Subjects
Engineering, Tokamak, business.industry, Nuclear engineering, Divertor, Plasma, Fusion power, Collisionality, law.invention, Heat flux, ASDEX Upgrade, law, Beta (plasma physics), Atomic physics, business
Abstract

Recent experiments in ASDEX Upgrade aimed at improving the physics base for ITER and DEMO to aid the design and prepare operation. In order to increase its exhaust capabilities and operational flexibility a new bulk W divertor as well as an adjustable cryo-pump had been installed prior to the 2014 campaign. In experiments with high field side pellet injection central electron densities twice as high as the Greenwald density limit could be achieved without strongly increasing the pedestal density and deleterious effect on confinement. Due to its large installed heating power a large normalized heat flux Psep/R=10 MWm−1 has been reached, representing 2/3 of the ITER value, under partially detached conditions with a peak target heat flux well below 10 MWm−2. The divertor load could be further reduced by increasing the core radiation still keeping the confinement in the range of H98y≈1. ELM suppression at low collisionality has been observed in a narrow spectral window in contrast to earlier results at high densities. The ITER Q=10 baseline scenario has been investigated, matching as close as possible the triangularity, the plasma beta, q95 and the distance the L-H threshold. It turned out that the ELMs frequency is low and consequently the energy ejected by a single ELM is very high and ELM mitigation appears to be difficult. As a possible alternative an improved H-Mode scenario has been developed achieving a similar performance at lower plasma current (and consequently higher q95). Experiments using ECCD with feedback controlled deposition have allowed successfully testing several control strategies for ITER, including automated control of (3,2) and (2,1) NTMs during a single discharge. Concerning advanced scenarios, experiments with central ctr-ECCD have been performed in order to modify the q-profile. A strong reversal of the q-profile could be stationary achieved and an internal transport barrier could be triggered. In disruption mitigation studies with massive gas injection (MGI) a runaway electron beam could be provoked and mitigated by a second MGI. Ongoing enhancements aim at the strengthening of the power supplies in order to allow full use of the installed heating power, the exchange of two ICRH antennas to reduce the W influx during ICRH and the upgrading of the ECRH system to 7–8 MW for 10s.

Published
2015
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11. Partial detachment of high power discharges in ASDEX Upgrade

Author

L. Casali, M. Wischmeier, L. Giannone, F. Reimold, M. Maraschek, M. Bernert, S. Potzel, A. Kallenbach, E. Viezzer, V. Rohde, J. Schweinzer, T. Eich, M. G. Dunne, A. Herrmann, M. Beurskens, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Nuclear and High Energy Physics, Materials science, Divertor, Radiation, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Electron cyclotron resonance, 010305 fluids & plasmas, Pedestal, ASDEX Upgrade, Heat flux, 0103 physical sciences, Thermoelectric effect, Atomic physics, 010306 general physics, Edge-localized mode
Abstract

Detachment of high power discharges is obtained in ASDEX Upgrade by simultaneous feedback control of core radiation and divertor radiation or thermoelectric currents by the injection of radiating impurities. So far 2/3 of the ITER normalized heat flux Psep/R = 15 MW m−1 has been obtained in ASDEX Upgrade under partially detached conditions with a peak target heat flux well below 10 MW m−2. When the detachment is further pronounced towards lower peak heat flux at the target, substantial changes in edge localized mode (ELM) behaviour, density and radiation distribution occur. The time-averaged peak heat flux at both divertor targets can be reduced below 2 MW m−2, which offers an attractive DEMO divertor scenario with potential for simpler and cheaper technical solutions. Generally, pronounced detachment leads to a pedestal and core density rise by about 20–40%, moderate (

Published
2015

12. The H-mode density limit in the full tungsten ASDEX Upgrade tokamak

Author

A. Huber, D. Carralero, F. Reimold, M. Bernert, Peter Lang, E. Viezzer, S. Potzel, H. Zohm, J. Schweinzer, A. Kallenbach, T. Eich, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Electron density, Tokamak, Materials science, Divertor, Plasma, Fusion power, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention, High-confinement mode, Nuclear Energy and Engineering, ASDEX Upgrade, Physics::Plasma Physics, law, Ionization, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

The high confinement mode (H-mode) is the operational scenario foreseen for ITER, DEMO and future fusion power plants. At high densities, which are favorable in order to maximize the fusion power, a back transition from the H-mode to the low confinement mode (L-mode) is observed. In present tokamaks, this H-mode density limit (HDL) occurs at densities on the order of, but below, the Greenwald density.In gas ramp discharges at the fully tungsten covered ASDEX Upgrade tokamak (AUG), four distinct operational phases are identified in the approach towards the HDL. These phases are a stable H-mode, a degrading H-mode, the breakdown of the H-mode and an L-mode. They are reproducible, quasi-stable plasma regimes and provide a framework in which the HDL can be further analyzed. During the evolution, energy losses are increased and a fueling limit is encountered. The latter is correlated to a plateau of electron density in the scrape-off layer (SOL). The well-known extension of the good confinement at high density with high triangularity is reflected in this scheme by extending the first phase to higher densities.In this work, two mechanisms are proposed, which can explain the experimental observations. The fueling limit is most likely correlated to an outward shift of the ionization profile. The additional energy loss channel is presumably linked to a regime of increased radial filament transport in the SOL. The SOL and divertor plasmas play a key role for both mechanisms, in line with the previous hypothesis that the HDL is edge-determined.The four phases are also observed in carbon covered AUG, although the HDL density exhibits a different dependency on the heating power and plasma current. This can be attributed to a changed energy loss channel in the presented scheme.

Published
2015
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13. A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA

Author

V. Bobkov, Daniele Milanesio, R. Bilato, Geert Verdoolaege, Helmut Faugel, V. Nikolaeva, I. Stepanov, E. Wolfrum, D. P. Coster, G. Siegl, J. Schweinzer, Marco Brambilla, A. Kallenbach, A. Mlynek, J.-M. Noterdaeme, R. Fischer, Riccardo Maggiora, L. Guimarais, F. Braun, R. D'Inca, H. Fünfgelder, and W. Suttrop

Subjects
Physics, Nuclear and High Energy Physics, Loop antenna, antenna impedance, Antenna measurement, Antenna aperture, ion cyclotron range of frequencies, Input impedance, Antenna factor, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Computational physics, coupling, Nuclear magnetic resonance, ASDEX Upgrade, 0103 physical sciences, Reflection coefficient, Antenna (radio), 010306 general physics
Abstract

New antenna diagnostics on the ASDEX Upgrade, in the form of voltage and current probe pairs on the feeding lines of each ion cyclotron range of frequencies antenna, close to the input ports, have made it possible to study in detail the behavior of the ASDEX Upgrade two-strap antenna under changing loading conditions, and compare these measurements with the results of simulations using the TOPICA code. The present work extends previous studies by using the input impedance (more precisely, the complex voltage reflection coefficient Gamma) on each antenna port for comparison, instead of the more commonly used loading resistance or coupled power. The electron density profiles used for the simulation were reconstructed from the deuterium-carbon-nitrogen interferometer and lithium beam emission spectroscopy measurements, edge-localized mode-synchronized and averaged over time intervals from 10 to 200 ms depending on the case; 112 cases were compared from seven ASDEX Upgrade discharges with widely different plasma parameters and two operating frequencies (30 and 36.5 MHz). Very good agreement in vertical bar Gamma vertical bar was found with the measurements on antenna 3 (

Published
2015
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14. Assessment of the baseline scenario at q 95 ~ 3 for ITER.

Author

experts, ITPA-IOS T. G. members and, A.C.C. Sips, C. Kessel, P. Lomas, F. Rimini, I. Nunes, J. Schweinzer, J. Hobirk, T. Pütterich, J. Stober, team, The ASDEX Upgrade, W.M. Solomon, F. Turco, team, The DIII-D, T.C. Luce, S.H. Kim, P.C. de Vries, S. Wolfe, team, The C-Mod, and H. Urano

Subjects
PLASMA flow, PLASMA confinement, PLASMA density, SIMULATION methods & models
Abstract

The International Tokamak Physics Activity topical group on integrated operational scenarios has compiled a database of stationary H-mode discharges at q95 ~ 3 from AUG, C-Mod, DIII-D, JET and JT-60U, for both carbon wall and high-Z metal wall experiments with ~3300 entries. The analyses focus on discharges that are stationary for  ⩾5 thermal energy confinement times to evaluate the baseline scenario proposed for ITER at 15 MA for achieving its goals of Q  =  10, fusion power of 500 MW at normalised pressure, βN  =  1.8 and normalised confinement as predicted by the standard H-mode scaling, H98y2  =  1. With the data restricted to stationary H-modes at q95 ~ 3, the database shows significant variation of thermal energy confinement compared to the standard H-mode scaling (IPB98(y,2)) in dimensionless form. The data show similar scaling with normalised gyro-radius, but more favourable scaling towards lower collision frequency and more favourable scaling with plasma beta. Using all the engineering variables employed in IPB98(y,2), results in an overfit due to correlations among the data. Moreover, there are significant residual trends in the confinement for plasma current, device size, loss power, and in particular for the plasma density. Significant differences between results obtained for devices with a carbon wall and high-Z metal wall are observed in the data, with data from carbon wall devices providing a larger operating space, encompassing ITER parameters or even exceeding them. H-modes in high-Z metal wall devices have, so-far, not accessed conditions at low collision frequencies, have lower normalised confinement (H98y2 ~ 0.8–0.9) at low input power or beta, achieving H98y2 ~ 1.0 only at input powers two times the L- to H-mode transition scaling predictions and at βN ~ 2.0. Hence, only the best H-modes with high-Z metal walls reach ITER baseline performance requirements. The data show that operating at high plasma density, with line-averaged density at 85% of Greenwald density is achievable for H98y2  >  0.95 for a range of plasma configurations, and that operation at low plasma inductance with li(3) ~ 0.7–0.75 is feasible. Scenario simulations employed for projecting the plasma performance in ITER should incorporate a lower thermal confinement at low plasma beta for the entry to burn and provide projections using higher levels of plasma core radiation by plasma impurities. Moreover, ITER projections should not subtract the core radiation in the evaluation of the thermal confinement time and H98y2, to allow a fair comparison with experimental data currently available. From the data presented here, it is likely that in ITER the energy confinement time will not increase with plasma density and will have no degradation with plasma beta. The analyses indicate that the data at q95 ~ 3 are consistent with achievement of the ITER mission goals at 15 MA. [ABSTRACT FROM AUTHOR]

Published
2018
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15. Development of the Q  =  10 scenario for ITER on ASDEX Upgrade (AUG).

Author

J. Schweinzer, M. Beurskens, L. Frassinetti, E. Joffrin, V. Bobkov, R. Dux, R. Fischer, C. Fuchs, A. Kallenbach, C. Hopf, P.T. Lang, A. Mlynek, T. Pütterich, F. Ryter, J. Stober, G. Tardini, E. Wolfrum, H. Zohm, Team, the EUROfusion MST1, and Team, the ASDEX Upgrade

Subjects
TOKAMAKS, MAGNETIC confinement, IMPURITY centers, PLASMA physics
Abstract

The development of the baseline H-mode scenario foreseen for ITER on the ASDEX Upgrade tokamak, i.e. discharges at q95  =  3, relatively low βN ~ 1.8, high normalized density n/nGW ~ 0.85 and high triangularity δ  =  0.4, focused on the integration of elements foreseen for ITER and available on ASDEX Upgrade, such as ELM mitigation techniques and impurity seeding in combination with a metallic wall. Values for density and energy confinement simultaneously came close to the requirements of the ITER baseline scenario as long as βN stayed above 2. At lower heating power and thus lower βN normalized energy confinement H98y2 ~ 0.85 is obtained. It has been found that stationary discharges are not easily achieved under these conditions due to the low natural ELM frequency occurring at the low q95/high δ operational point. Up until now the ELM parameters were uncontrollable with the tools developed in other scenarios. Therefore studies on an alternative operational point at higher βN and q95 have been conducted. In order to prepare for the ITER first non-activation operational phase, Helium operation has been investigated as well. [ABSTRACT FROM AUTHOR]

Published
2016
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16. The role of carbon and nitrogen on the H-mode confinement in ASDEX Upgrade with a metal wall.

Author

M.N.A. Beurskens, M.G. Dunne, L. Frassinetti, M. Bernert, M. Cavedon, R. Fischer, A. Järvinen, A. Kallenbach, F.M. Laggner, R.M. McDermott, S. Potzel, J. Schweinzer, G. Tardini, E. Viezzer, E. Wolfrum, Team, the ASDEX Upgrade, and team, the EUROfusion MST1

Subjects
CARBON, NITROGEN, METALS, TUNGSTEN, DENSE plasmas
Abstract

Carbon (CD4) and nitrogen (N2) have been seeded in ASDEX Upgrade (AUG) with a tungsten wall and have both led to a 20–30% confinement improvement. The reference plasma is a standard target plasma with Ip /BT  =  1 MA/2.5 T, total input power Ptot ~ 12 MW and normalized pressure of βN ~ 1.8. Carbon and nitrogen are almost perfectly exchangeable for the core, pedestal and divertor plasma in this experiment where impurity concentrations of C and N of 2% are achieved and Zeff only mildly increases from ~1.3 to ~1.7. As the radiation potentials of C and N are similar and peak well below 100 eV, both impurities act as divertor radiators and radiate well outside the pedestal region. The outer divertor is purposely kept in an attached state when C and N are seeded to avoid confinement degradation by detachment. As reported in earlier publications for nitrogen, carbon is also seen to reduce the high field side high density (the so-called HFSHD) in the scrape off layer above the inner divertor strike point by about 50%. This is accompanied by a confinement improvement for both low (δ ~ 0.25) and high (δ ~ 0.4) triangularity configurations for both seeding gases, due to an increase of pedestal temperature and stiff core temperature profiles. The electron density profiles show no apparent change due to the seeding. As an orthogonal effect, increasing the triangularity leads to an additionally increased pedestal density, independent of the impurity seeding. This experiment further closes the gap in understanding the confinement differences observed in carbon and metal wall devices; the absence of carbon can be substituted by nitrogen which leads to a similar confinement benefit. So far, no definite physics explanation for the confinement enhancement has been obtained, but the experimental observations in this paper provide input for further model development. [ABSTRACT FROM AUTHOR]

Published
2016
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17. A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA.

Author

I. Stepanov, J.-M. Noterdaeme, V. Bobkov, H. Faugel, D. Coster, D. Milanesio, R. Maggiora, G. Siegl, R. Bilato, M. Brambilla, G. Verdoolaege, F. Braun, H. Fünfgelder, R. D’Inca, W. Suttrop, A. Kallenbach, J. Schweinzer, E. Wolfrum, R. Fischer, and A. Mlynek

Subjects
CYCLOTRONS, ELECTRIC impedance, ELECTRIC potential, SIMULATION methods & models, OPERATIONS research
Abstract

New antenna diagnostics on the ASDEX Upgrade, in the form of voltage and current probe pairs on the feeding lines of each ion cyclotron range of frequencies antenna, close to the input ports, have made it possible to study in detail the behavior of the ASDEX Upgrade two-strap antenna under changing loading conditions, and compare these measurements with the results of simulations using the TOPICA code. The present work extends previous studies by using the input impedance (more precisely, the complex voltage reflection coefficient ) on each antenna port for comparison, instead of the more commonly used loading resistance or coupled power. The electron density profiles used for the simulation were reconstructed from the deuterium-carbon-nitrogen interferometer and lithium beam emission spectroscopy measurements, edge-localized mode-synchronized and averaged over time intervals from 10 to 200 ms depending on the case; 112 cases were compared from seven ASDEX Upgrade discharges with widely different plasma parameters and two operating frequencies (30 and 36.5 MHz). Very good agreement in was found with the measurements on antenna 3 (<3% averaged over a shot), and good agreement was found with antennas 1 and 2 (<10%); the code reproduced the correct trend in loading resistance in a significant majority of cases, although the discrepancies in the absolute values were rather high (up to  ∼50%) due to high reflection. Sources of discrepancy are discussed. [ABSTRACT FROM AUTHOR]

Published
2015
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18. Impact of W on scenario simulations for ITER.

Author

G.M.D. Hogeweij, V. Leonov, J. Schweinzer, A.C.C. Sips, C. Angioni, G. Calabrò, R. Dux, A. Kallenbach, E. Lerche, C. Maggi, Th. Pütterich, group, ITPA Integrated Operating Scenarios topical, team, ASDEX Upgrade, and Contributors, JET

Subjects
FUSION reactor divertors, RADIOACTIVE substances, TUNGSTEN, BERYLLIUM compounds, NUCLEAR physics experiments
Abstract

In preparation of ITER operation, large machines have replaced their wall and divertor material to W (ASDEX Upgrade) or a combination of Be for the wall and W for the divertor (JET). Operation in these machines has shown that the influx of W can have a significant impact on the discharge evolution, which has made modelling of this impact for ITER an urgent task. This paper reports on such modelling efforts. Maximum tolerable W concentrations have been determined for various scenarios, both for the current ramp-up and flat-top phase. Results of two independent methods are presented, based on the codes ZIMPUR plus ASTRA and CRONOS, respectively. Both methods have been tested and benchmarked against ITER-like Ip RU experiments at JET. It is found that W significantly disturbs the discharge evolution when the W concentration approaches ∼10−4; this critical level varies somewhat between scenarios. [ABSTRACT FROM AUTHOR]

Published
2015
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19. Partial detachment of high power discharges in ASDEX Upgrade.

Author

A. Kallenbach, M. Bernert, M. Beurskens, L. Casali, M. Dunne, T. Eich, L. Giannone, A. Herrmann, M. Maraschek, S. Potzel, F. Reimold, V. Rohde, J. Schweinzer, E. Viezzer, M. Wischmeier, and Team, the ASDEX Upgrade

Subjects
PLASMA flow, EDGE-localized modes (Plasma instabilities), FEEDBACK control systems, PLASMA confinement, HEAT flux, ELECTRON cyclotron resonance heating, DETACHMENT reactions
Abstract

Detachment of high power discharges is obtained in ASDEX Upgrade by simultaneous feedback control of core radiation and divertor radiation or thermoelectric currents by the injection of radiating impurities. So far 2/3 of the ITER normalized heat flux Psep/R = 15 MW m−1 has been obtained in ASDEX Upgrade under partially detached conditions with a peak target heat flux well below 10 MW m−2. When the detachment is further pronounced towards lower peak heat flux at the target, substantial changes in edge localized mode (ELM) behaviour, density and radiation distribution occur. The time-averaged peak heat flux at both divertor targets can be reduced below 2 MW m−2, which offers an attractive DEMO divertor scenario with potential for simpler and cheaper technical solutions. Generally, pronounced detachment leads to a pedestal and core density rise by about 20–40%, moderate (<20%) confinement degradation and a reduction of ELM size. For AUG conditions, some operational challenges occur, like the density cut-off limit for X-2 electron cyclotron resonance heating, which is used for central tungsten control. [ABSTRACT FROM AUTHOR]

Published
2015
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20. The H-mode density limit in the full tungsten ASDEX Upgrade tokamak.

Author

M Bernert, T Eich, A Kallenbach, D Carralero, P T Lang, S Potzel, F Reimold, J Schweinzer, E Viezzer, H Zohm, and A Huber

Subjects
ELECTRON density, POWER plants, TOKAMAKS, ENERGY dissipation, IONIZATION (Atomic physics)
Abstract

The high confinement mode (H-mode) is the operational scenario foreseen for ITER, DEMO and future fusion power plants. At high densities, which are favorable in order to maximize the fusion power, a back transition from the H-mode to the low confinement mode (L-mode) is observed. In present tokamaks, this H-mode density limit (HDL) occurs at densities on the order of, but below, the Greenwald density.In gas ramp discharges at the fully tungsten covered ASDEX Upgrade tokamak (AUG), four distinct operational phases are identified in the approach towards the HDL. These phases are a stable H-mode, a degrading H-mode, the breakdown of the H-mode and an L-mode. They are reproducible, quasi-stable plasma regimes and provide a framework in which the HDL can be further analyzed. During the evolution, energy losses are increased and a fueling limit is encountered. The latter is correlated to a plateau of electron density in the scrape-off layer (SOL). The well-known extension of the good confinement at high density with high triangularity is reflected in this scheme by extending the first phase to higher densities.In this work, two mechanisms are proposed, which can explain the experimental observations. The fueling limit is most likely correlated to an outward shift of the ionization profile. The additional energy loss channel is presumably linked to a regime of increased radial filament transport in the SOL. The SOL and divertor plasmas play a key role for both mechanisms, in line with the previous hypothesis that the HDL is edge-determined.The four phases are also observed in carbon covered AUG, although the HDL density exhibits a different dependency on the heating power and plasma current. This can be attributed to a changed energy loss channel in the presented scheme. [ABSTRACT FROM AUTHOR]

Published
2015
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