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1. Overview of the first Wendelstein 7-X long pulse campaign with fully water-cooled plasma facing components

Author

O. Grulke, C. Albert, J.A. Alcuson Belloso, P. Aleynikov, K. Aleynikova, A. Alonso, G. Anda, T. Andreeva, M. Arvanitou, E. Ascasibar, E. Aymerich, K. Avramidis, J.-P. Bähner, S.-G. Baek, M. Balden, J. Baldzuhn, S. Ballinger, M. Banduch, S. Bannmann, A. Bañón Navarro, L. Baylor, C.D. Beidler, M. Beurskens, C. Biedermann, G. Birkenmeier, T. Bluhm, D. Boeckenhoff, D. Boeyaert, D. Bold, M. Borchardt, D. Borodin, H.-S. Bosch, H. Bouvain, S. Bozhenkov, T. Bräuer, H. Braune, C. Brandt, S. Brezinsek, K.J. Brunner, C. Büschel, R. Bussiahn, A. Buzás, B. Buttenschoen, V. Bykov, I. Calvo, A. Cappa, F. Carovani, D. Carralero, A. Carls, B. Carvalho, D. Castaño-Bardawil, N. Chaudhary, I. Chelis, S. Chen, D. Cipciar, J.W. Coenen, G. Conway, M. Cornelissen, Y. Corre, P. Costello, K. Crombe, G. Cseh, B. Csillag, H.I. Cu Castillo, G. Czymek, H. Damm, R.J. Davies, C. Day, S. Degenkolbe, R. De Wolf, W. Dekeyser, A. Demby, P. Despontin, C.P. Dhard, A. Dinklage, F.A. d’Isa, T. Dittmar, M. Dreval, M. Drevlak, P. Drews, J. Droste, D. Dunai, C. Dyhring, P. van Eeten, E. Edlund, M. Endler, D.A. Ennis, F.J. Escoto, M.S. Espinosa, T. Estrada, D. Fehling, L. Feuerstein, J. Fellinger, Y. Feng, D.L.C. Fernando, S. Fischer, E.R. Flom, O. Ford, T. Fornal, J. Frank, H. Frerichs, G. Fuchert, G. Gantenbein, Y. Gao, K. Garcia, I. García-Cortés, J.M. García-Regaña, B. Geiger, J. Geiger, P. Geissler, M. Gerard, G. Godino-Sedano, T. Gonda, A. González, A. Goriaev, D. Gradic, M. Grahl, H. Greuner, E. Grigore, M. Gruca, J.F. Guerrero Arnaiz, V. Haak, L. van Ham, K. Hammond, B. Hamstra, X. Han, S.K. Hansen, J. Harris, D. Hartmann, D. Hathiramani, S. Hegedus, S. Heinrich, P. Helander, F. Henke, S. Henneberg, L. Henschke, M. Hirsch, U. Hoefel, K. Hoefler, S. Hoermann, K.-P. Hollfeld, A. Holtz, D. Höschen, M. Houry, J. Huang, M. Hubeny, K. Hunger, D. Hwangbo, K. Ida, Y. Igitkhanov, S. Illy, Z. Ioannidis, M. Jablczynska, S. Jablonski, B. Jabłoński, B. Jagielski, M. Jakubowski, J. Jelonnek, F. Jenko, J. Jin, A. Johansson, G. Jouniaux, S. Kajita, J.-P. Kallmeyer, U. Kamionka, W. Kasparek, C. Kawan, Ye. O. Kazakov, N. Kenmochi, W. Kernbichler, A.K. Kharwandikar, M. Khokhlov, C. Killer, A. Kirschner, R. Kleiber, C.C. Klepper, T. Klinger, J. Knauer, A. Knieps, M. Kobayashi, G. Kocsis, Y. Kolesnichenko, A. Könies, J. Kontula, P. Kornejew, S.A. Korteweg, J. Koschinsky, J. Koster, Y. Kovtun, A. Krämer-Flecken, M. Krause, T. Kremeyer, L. Krier, D.M. Kriete, M. Krychowiak, I. Ksia¸zek, M. Kubkowska, M.D. Kuczyński, D. Kulla, A. Kumar, T. Kurki-Suonio, I. Kuzmych, S. Kwak, V. Lancelotti, A. Langenberg, H. Laqua, H.P. Laqua, M.R. Larsen, S. Lazerson, C. Lechte, B. Lee, A. LeViness, M. Lewerentz, Y. Liang, L. Liao, A. Litnovsky, J. Liu, J. Loizu, R. Lopez-Cansino, L.D. Lopez Rodriguez, A. Lorenz, R. Lunsford, Y. Luo, V. Lutsenko, N. Maaziz, M. Machielsen, R. Mackenbach, D. Makowski, E. Maragkoudakis, O. Marchuk, M. Markl, S. Marsen, J. Martínez, N. Marushchenko, S. Masuzaki, D.A. Maurer, M. Mayer, K.J. McCarthy, P. McNeely, D. Medina Roque, J. Meineke, S. Meitner, S. vaz Mendes, A. Menzel-Barbara, B. van Milligen, A. Mishchenko, V. Moiseenko, A. Möller, S. Möller, D. Moseev, G. Motojima, S. Mulas, P. Mulholland, M. Nagel, D. Nagy, Y. Narbutt, D. Naujoks, P. Nelde, R. Neu, O. Neubauer, U. Neuner, D. Nicolai, S. Nielsen, C. Nührenberg, R. Ochoukov, G. Offermanns, J. Ongena, J.W. Oosterbeek, M. Otte, N. Pablant, N. Panadero Alvarez, A. Pandey, G. Partesotti, E.A. Pasch, R. Pavlichenko, E. Pawelec, T.S. Pedersen, V. Perseo, B. Peterson, F. Pisano, B. Plaum, G. Plunk, L. Podavini, N.S. Polei, P. Poloskei, S. Ponomarenko, P. Pons-Villalonga, M. Porkolab, J. Proll, M.J. Pueschel, A. Puig Sitjes, R. Ragona, K. Rahbarnia, M. Rasiński, J. Rasmussen, D. Refy, F. Reimold, M. Richou, J.S. Riemann, K. Riße, J. de la Riva Villén, G. Roberg-Clark, E. Rodriguez, V. Rohde, J. Romazanov, T. Romba, D. Rondeshagen, M. Rud, T. Ruess, T. Rummel, A. Runov, C. Ruset, N. Rust, L. Ryc, T. Rzesnicki, M. Salewski, E. Sánchez, L. Sanchis Sanchez, G. Satheeswaran, J. Schacht, E. Scharff, J. Schilling, G. Schlisio, K. Schmid, J.C. Schmitt, O. Schmitz, M. Schneider, M. Van Schoor, T. Schröder, R. Schroeder, B. Schweer, S. Sereda, B. Shanahan, G. Sias, S. Simko, L. Singh, Y. Siusko, C. Slaby, M. Śle¸czka, B.S. Smith, D.R. Smith, H. Smith, M. Spolaore, A. Spring, T. Stange, A. von Stechow, I. Stepanov, M. Stern, U. Stroth, Y. Suzuki, C. Swee, L. Syrocki, T. Szabolics, T. Szepesi, R. Takacs, H. Takahashi, N. Tamura, C. Tantos, J. Terry, S. Thiede, H. Thienpondt, H. Thomsen, M. Thumm, T. Thun, S. Togo, T. Tork, H. Trimino Mora, A. Tsikouras, Y. Turkin, L. Vano, S. Varoutis, M. Vecsei, J.L. Velasco, M. Verstraeten, M. Vervier, E. Viezzer, J. Wagner, E. Wang, F. Wang, M. Wappl, F. Warmer, T. Wegner, Y. Wei, G. Weir, N. Wendler, U. Wenzel, A. White, F. Wilms, T. Windisch, A. Winter, V. Winters, R. Wolf, G. Wurden, P. Xanthopoulos, H.M. Xiang, S. Xu, H. Yamada, J. Yang, R. Yi, M. Yokoyama, B. Zamorski, M. Zanini, M. Zarnstorff, D. Zhang, S. Zhou, J. Zhu, J. Zimmermann, A. Zocco, and S. Zoletnik

Subjects
stellarator, long-pulse operation, magnetic fusion confinement, divertor detachment, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

After a long device enhancement phase, scientific operation resumed in 2022. The main new device components are the water cooling of all plasma facing components and the new water-cooled high heat flux divertor units. Water cooling allowed for the first long-pulse operation campaign. A maximum discharge length of 8 min was achieved with a total heating energy of 1.3 GJ. Safe divertor operation was demonstrated in attached and detached mode. Stable detachment is readily achieved in some magnetic configurations but requires impurity seeding in configurations with small magnetic pitch angle within the edge islands. Progress was made in the characterization of transport mechanisms across edge magnetic islands: Measurement of the potential distribution and flow pattern reveals that the islands are associated with a strong poloidal drift, which leads to rapid convection of energy and particles from the last closed flux surface into the scrape-off layer. Using the upgraded plasma heating systems, advanced heating scenarios were developed, which provide improved energy confinement comparable to the scenario, in which the record triple product for stellarators was achieved in the previous operation campaign. However, a magnetic configuration-dependent critical heating power limit of the electron cyclotron resonance heating was observed. Exceeding the respective power limit leads to a degradation of the confinement.

Published
2024
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2. Validation of a synthetic fast ion loss detector model for Wendelstein 7-X

Author

A. LeViness, S.A. Lazerson, A. Jansen van Vuuren, J. Rueda-Rueda, M. Beurskens, S. Bozhenkov, K.J. Brunner, O.P. Ford, G. Fuchert, M. Garcìa-Muñoz, M. Isobe, C. Killer, J. Knauer, K. Ogawa, N. Pablant, E. Pasch, P. Poloskei, T. Romba, and the W7-X Team

Subjects
fusion, stellarator, Wendelstein 7-X, diagnostics, fast ions, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

We present the first validated synthetic diagnostic for fast ion loss detectors (FILDs) in the Wendelstein 7-X (W7-X) stellarator. This model has been developed on, and validated against experimental data from, a FILD provided by the National Institute for Fusion Science (NIFS-FILD), with potential future applicability to the existing Faraday Cup FILD (FC-FILD) on W7-X as well as the scintillating FILD (S-FILD) currently under development. A workflow combining Monte Carlo codes BEAMS3D and ASCOT5 is used to track fast ions produced by neutral beam injection from the moment of ionization until they are thermalized or lost from the last closed flux surface, and from there to a virtual plane which serves as a projection of the entrance aperture to the FILD. Simulations in ASCOT5 are analyzed via a geometric method to determine the probability of transmission through the FILD aperture and onto the detector as a function of normalized momentum, pitch angle, gyrophase, and position at the virtual plane. This probability is then applied to the simulated ions arriving from the plasma, producing a simulated signal from a computationally tractable number of simulated fast ions. Simulated signals are presented for two W7-X experiments with neutral beam injection and quantitatively compared with experimental measurements from the NIFS-FILD diagnostic. An estimate of the frequency of charge-exchange with neutral particles in the edge is performed, and it is found that this process may have a significant impact on the measured signals.

Published
2024
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3. 4D and 5D phase-space tomography using slowing-down physics regularization

Author

B.S. Schmidt, M. Salewski, D. Moseev, M. Baquero-Ruiz, P.C. Hansen, J. Eriksson, O. Ford, G. Gorini, H. Järleblad, Ye O. Kazakov, D. Kulla, S. Lazerson, J.E. Mencke, D. Mykytchuk, M. Nocente, P. Poloskei, M. Rud, A. Snicker, L. Stagner, S. Äkäslompolo, and the W7-X Team

Subjects
fast ions, tomography, slowing-down, NBI, Tokamak, stellarator, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be distinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions.

Published
2023
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6. Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

Author

Thomas Sunn Pedersen, I. Abramovic, P. Agostinetti, M. Agredano Torres, S. Äkäslompolo, J. Alcuson Belloso, P. Aleynikov, K. Aleynikova, M. Alhashimi, A. Ali, N. Allen, A. Alonso, G. Anda, T. Andreeva, C. Angioni, A. Arkhipov, A. Arnold, W. Asad, E. Ascasibar, M.-H. Aumeunier, K. Avramidis, E. Aymerich, S.-G. Baek, J. Bähner, A. Baillod, M. Balden, J. Baldzuhn, S. Ballinger, M. Banduch, S. Bannmann, A. Banon Navarro, A. Bañón Navarro, T. Barbui, C. Beidler, C. Belafdil, A. Bencze, A. Benndorf, M. Beurskens, C. Biedermann, O. Biletskyi, B. Blackwell, M. Blatzheim, T. Bluhm, D. Böckenhoff, G. Bongiovi, M. Borchardt, D. Borodin, J. Boscary, H. Bosch, T. Bosmann, B. Böswirth, L. Böttger, A. Bottino, S. Bozhenkov, R. Brakel, C. Brandt, T. Bräuer, H. Braune, S. Brezinsek, K. Brunner, S. Buller, R. Burhenn, R. Bussiahn, B. Buttenschön, A. Buzás, V. Bykov, I. Calvo, K. Camacho Mata, I. Caminal, B. Cannas, A. Cappa, A. Carls, F. Carovani, M. Carr, D. Carralero, B. Carvalho, J. Casas, D. Castano-Bardawil, F. Castejon, N. Chaudhary, I. Chelis, A. Chomiczewska, J.W. Coenen, M. Cole, F. Cordella, Y. Corre, K. Crombe, G. Cseh, B. Csillag, H. Damm, C. Day, M. de Baar, E. De la Cal, S. Degenkolbe, A. Demby, S. Denk, C. Dhard, A. Di Siena, A. Dinklage, T. Dittmar, M. Dreval, M. Drevlak, P. Drewelow, P. Drews, D. Dunai, E. Edlund, F. Effenberg, G. Ehrke, M. Endler, D.A. Ennis, F.J. Escoto, T. Estrada, E. Fable, N. Fahrenkamp, A. Fanni, J. Faustin, J. Fellinger, Y. Feng, W. Figacz, E. Flom, O. Ford, T. Fornal, H. Frerichs, S. Freundt, G. Fuchert, M. Fukuyama, F. Füllenbach, G. Gantenbein, Y. Gao, K. Garcia, J.M. García Regaña, I. García-Cortés, J. Gaspar, D.A. Gates, J. Geiger, B. Geiger, L. Giudicotti, A. González, A. Goriaev, D. Gradic, M. Grahl, J.P. Graves, J. Green, E. Grelier, H. Greuner, S. Groß, H. Grote, M. Groth, M. Gruca, O. Grulke, M. Grün, J. Guerrero Arnaiz, S. Günter, V. Haak, M. Haas, P. Hacker, A. Hakola, A. Hallenbert, K. Hammond, X. Han, S.K. Hansen, J.H. Harris, H. Hartfuß, D. Hartmann, D. Hathiramani, R. Hatzky, J. Hawke, S. Hegedus, B. Hein, B. Heinemann, P. Helander, S. Henneberg, U. Hergenhahn, C. Hidalgo, F. Hindenlang, M. Hirsch, U. Höfel, K.P. Hollfeld, A. Holtz, D. Hopf, D. Höschen, M. Houry, J. Howard, X. Huang, M. Hubeny, S. Hudson, K. Ida, Y. Igitkhanov, V. Igochine, S. Illy, C. Ionita-Schrittwieser, M. Isobe, M. Jabłczyńska, S. Jablonski, B. Jagielski, M. Jakubowski, A. Jansen van Vuuren, J. Jelonnek, F. Jenko, T. Jensen, H. Jenzsch, P. Junghanns, J. Kaczmarczyk, J. Kallmeyer, U. Kamionka, M. Kandler, S. Kasilov, Y. Kazakov, D. Kennedy, A. Kharwandikar, M. Khokhlov, C. Kiefer, C. Killer, A. Kirschner, R. Kleiber, T. Klinger, S. Klose, J. Knauer, A. Knieps, F. Köchl, G. Kocsis, Ya.I. Kolesnichenko, A. Könies, R. König, J. Kontula, P. Kornejew, J. Koschinsky, M.M. Kozulia, A. Krämer-Flecken, R. Krampitz, M. Krause, N. Krawczyk, T. Kremeyer, L. Krier, D.M. Kriete, M. Krychowiak, I. Ksiazek, M. Kubkowska, M. Kuczynski, G. Kühner, A. Kumar, T. Kurki-Suonio, S. Kwak, M. Landreman, P.T. Lang, A. Langenberg, H.P. Laqua, H. Laqua, R. Laube, S. Lazerson, M. Lewerentz, C. Li, Y. Liang, Ch. Linsmeier, J. Lion, A. Litnovsky, S. Liu, J. Lobsien, J. Loizu, J. Lore, A. Lorenz, U. Losada, F. Louche, R. Lunsford, V. Lutsenko, M. Machielsen, F. Mackel, J. Maisano-Brown, O. Maj, D. Makowski, G. Manduchi, E. Maragkoudakis, O. Marchuk, S. Marsen, E. Martines, J. Martinez-Fernandez, M. Marushchenko, S. Masuzaki, D. Maurer, M. Mayer, K.J. McCarthy, O. Mccormack, P. McNeely, H. Meister, B. Mendelevitch, S. Mendes, A. Merlo, A. Messian, A. Mielczarek, O. Mishchenko, B. Missal, R. Mitteau, V.E. Moiseenko, A. Mollen, V. Moncada, T. Mönnich, T. Morisaki, D. Moseev, G. Motojima, S. Mulas, M. Mulsow, M. Nagel, D. Naujoks, V. Naulin, T. Neelis, H. Neilson, R. Neu, O. Neubauer, U. Neuner, D. Nicolai, S.K. Nielsen, H. Niemann, T. Nishiza, T. Nishizawa, C. Nührenberg, R. Ochoukov, J. Oelmann, G. Offermanns, K. Ogawa, S. Okamura, J. Ölmanns, J. Ongena, J. Oosterbeek, M. Otte, N. Pablant, N. Panadero Alvarez, A. Pandey, E. Pasch, R. Pavlichenko, A. Pavone, E. Pawelec, G. Pechstein, G. Pelka, V. Perseo, B. Peterson, D. Pilopp, S. Pingel, F. Pisano, B. Plöckl, G. Plunk, P. Pölöskei, B. Pompe, A. Popov, M. Porkolab, J. Proll, M.J. Pueschel, M.-E. Puiatti, A. Puig Sitjes, F. Purps, K. Rahbarnia, M. Rasiński, J. Rasmussen, A. Reiman, F. Reimold, M. Reisner, D. Reiter, M. Richou, R. Riedl, J. Riemann, K. Riße, G. Roberg-Clark, V. Rohde, J. Romazanov, D. Rondeshagen, P. Rong, L. Rudischhauser, T. Rummel, K. Rummel, A. Runov, N. Rust, L. Ryc, P. Salembier, M. Salewski, E. Sanchez, S. Satake, G. Satheeswaran, J. Schacht, E. Scharff, F. Schauer, J. Schilling, G. Schlisio, K. Schmid, J. Schmitt, O. Schmitz, W. Schneider, M. Schneider, P. Schneider, R. Schrittwieser, T. Schröder, M. Schröder, R. Schroeder, B. Schweer, D. Schwörer, E. Scott, B. Shanahan, G. Sias, P. Sichta, M. Singer, P. Sinha, S. Sipliä, C. Slaby, M. Sleczka, H. Smith, J. Smoniewski, E. Sonnendrücker, M. Spolaore, A. Spring, R. Stadler, D. Stańczak, T. Stange, I. Stepanov, L. Stephey, J. Stober, U. Stroth, E. Strumberger, C. Suzuki, Y. Suzuki, J. Svensson, T. Szabolics, T. Szepesi, M. Szücs, F.L. Tabarés, N. Tamura, A. Tancetti, C. Tantos, J. Terry, H. Thienpondt, H. Thomsen, M. Thumm, J.M. Travere, P. Traverso, J. Tretter, E. Trier, H. Trimino Mora, T. Tsujimura, Y. Turkin, A. Tykhyi, B. Unterberg, P. van Eeten, B.Ph. van Milligen, M. van Schoor, L. Vano, S. Varoutis, M. Vecsei, L. Vela, J.L. Velasco, M. Vervier, N. Vianello, H. Viebke, R. Vilbrandt, G. Vogel, N. Vogt, C. Volkhausen, A. von Stechow, F. Wagner, E. Wang, H. Wang, F. Warmer, T. Wauters, L. Wegener, T. Wegner, G. Weir, U. Wenzel, A. White, F. Wilde, F. Wilms, T. Windisch, M. Winkler, A. Winter, V. Winters, R. Wolf, A.M. Wright, G.A. Wurden, P. Xanthopoulos, S. Xu, H. Yamada, H. Yamaguchi, M. Yokoyama, M. Yoshinuma, Q. Yu, M. Zamanov, M. Zanini, M. Zarnstorff, D. Zhang, S. Zhou, J. Zhu, C. Zhu, M. Zilker, A. Zocco, H. Zohm, S. Zoletnik, L. Zsuga, Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. GPI - Grup de Processament d'Imatge i Vídeo, Universitat Politècnica de Catalunya. GREO - Grup de Recerca en Enginyeria Òptica, Pedersen, T, Abramovic, I, Agostinetti, P, Torres, M, Akaslompolo, S, Belloso, J, Aleynikov, P, Aleynikova, K, Alhashimi, M, Ali, A, Allen, N, Alonso, A, Anda, G, Andreeva, T, Angioni, C, Arkhipov, A, Arnold, A, Asad, W, Ascasibar, E, Aumeunier, M, Avramidis, K, Aymerich, E, Baek, S, Bahner, J, Baillod, A, Balden, M, Baldzuhn, J, Ballinger, S, Banduch, M, Bannmann, S, Navarro, A, Barbui, T, Beidler, C, Belafdil, C, Bencze, A, Benndorf, A, Beurskens, M, Biedermann, C, Biletskyi, O, Blackwell, B, Blatzheim, M, Bluhm, T, Bockenhoff, D, Bongiovi, G, Borchardt, M, Borodin, D, Boscary, J, Bosch, H, Bosmann, T, Boswirth, B, Bottger, L, Bottino, A, Bozhenkov, S, Brakel, R, Brandt, C, Brauer, T, Braune, H, Brezinsek, S, Brunner, K, Buller, S, Burhenn, R, Bussiahn, R, Buttenschon, B, Buzas, A, Bykov, V, Calvo, I, Mata, K, Caminal, I, Cannas, B, Cappa, A, Carls, A, Carovani, F, Carr, M, Carralero, D, Carvalho, B, Casas, J, Castano-Bardawil, D, Castejon, F, Chaudhary, N, Chelis, I, Chomiczewska, A, Coenen, J, Cole, M, Cordella, F, Corre, Y, Crombe, K, Cseh, G, Csillag, B, Damm, H, Day, C, de Baar, M, De la Cal, E, Degenkolbe, S, Demby, A, Denk, S, Dhard, C, Di Siena, A, Dinklage, A, Dittmar, T, Dreval, M, Drevlak, M, Drewelow, P, Drews, P, Dunai, D, Edlund, E, Effenberg, F, Ehrke, G, Endler, M, Ennis, D, Escoto, F, Estrada, T, Fable, E, Fahrenkamp, N, Fanni, A, Faustin, J, Fellinger, J, Feng, Y, Figacz, W, Flom, E, Ford, O, Fornal, T, Frerichs, H, Freundt, S, Fuchert, G, Fukuyama, M, Fullenbach, F, Gantenbein, G, Gao, Y, Garcia, K, Regana, J, Garcia-Cortes, I, Gaspar, J, Gates, D, Geiger, J, Geiger, B, Giudicotti, L, Gonzalez, A, Goriaev, A, Gradic, D, Grahl, M, Graves, J, Green, J, Grelier, E, Greuner, H, Gross, S, Grote, H, Groth, M, Gruca, M, Grulke, O, Grun, M, Arnaiz, J, Gunter, S, Haak, V, Haas, M, Hacker, P, Hakola, A, Hallenbert, A, Hammond, K, Han, X, Hansen, S, Harris, J, Hartfuss, H, Hartmann, D, Hathiramani, D, Hatzky, R, Hawke, J, Hegedus, S, Hein, B, Heinemann, B, Helander, P, Henneberg, S, Hergenhahn, U, Hidalgo, C, Hindenlang, F, Hirsch, M, Hofel, U, Hollfeld, K, Holtz, A, Hopf, D, Hoschen, D, Houry, M, Howard, J, Huang, X, Hubeny, M, Hudson, S, Ida, K, Igitkhanov, Y, Igochine, V, Illy, S, Ionita-Schrittwieser, C, Isobe, M, Jablczynska, M, Jablonski, S, Jagielski, B, Jakubowski, M, van Vuuren, A, Jelonnek, J, Jenko, F, Jensen, T, Jenzsch, H, Junghanns, P, Kaczmarczyk, J, Kallmeyer, J, Kamionka, U, Kandler, M, Kasilov, S, Kazakov, Y, Kennedy, D, Kharwandikar, A, Khokhlov, M, Kiefer, C, Killer, C, Kirschner, A, Kleiber, R, Klinger, T, Klose, S, Knauer, J, Knieps, A, Kochl, F, Kocsis, G, Kolesnichenko, Y, Konies, A, Konig, R, Kontula, J, Kornejew, P, Koschinsky, J, Kozulia, M, Kramer-Flecken, A, Krampitz, R, Krause, M, Krawczyk, N, Kremeyer, T, Krier, L, Kriete, D, Krychowiak, M, Ksiazek, I, Kubkowska, M, Kuczynski, M, Kuhner, G, Kumar, A, Kurki-Suonio, T, Kwak, S, Landreman, M, Lang, P, Langenberg, A, Laqua, H, Laube, R, Lazerson, S, Lewerentz, M, Li, C, Liang, Y, Linsmeier, C, Lion, J, Litnovsky, A, Liu, S, Lobsien, J, Loizu, J, Lore, J, Lorenz, A, Losada, U, Louche, F, Lunsford, R, Lutsenko, V, Machielsen, M, Mackel, F, Maisano-Brown, J, Maj, O, Makowski, D, Manduchi, G, Maragkoudakis, E, Marchuk, O, Marsen, S, Martines, E, Martinez-Fernandez, J, Marushchenko, M, Masuzaki, S, Maurer, D, Mayer, M, Mccarthy, K, Mccormack, O, Mcneely, P, Meister, H, Mendelevitch, B, Mendes, S, Merlo, A, Messian, A, Mielczarek, A, Mishchenko, O, Missal, B, Mitteau, R, Moiseenko, V, Mollen, A, Moncada, V, Monnich, T, Morisaki, T, Moseev, D, Motojima, G, Mulas, S, Mulsow, M, Nagel, M, Naujoks, D, Naulin, V, Neelis, T, Neilson, H, Neu, R, Neubauer, O, Neuner, U, Nicolai, D, Nielsen, S, Niemann, H, Nishiza, T, Nishizawa, T, Nuhrenberg, C, Ochoukov, R, Oelmann, J, Offermanns, G, Ogawa, K, Okamura, S, Olmanns, J, Ongena, J, Oosterbeek, J, Otte, M, Pablant, N, Alvarez, N, Pandey, A, Pasch, E, Pavlichenko, R, Pavone, A, Pawelec, E, Pechstein, G, Pelka, G, Perseo, V, Peterson, B, Pilopp, D, Pingel, S, Pisano, F, Plockl, B, Plunk, G, Poloskei, P, Pompe, B, Popov, A, Porkolab, M, Proll, J, Pueschel, M, Puiatti, M, Sitjes, A, Purps, F, Rahbarnia, K, Rasinski, M, Rasmussen, J, Reiman, A, Reimold, F, Reisner, M, Reiter, D, Richou, M, Riedl, R, Riemann, J, Risse, K, Roberg-Clark, G, Rohde, V, Romazanov, J, Rondeshagen, D, Rong, P, Rudischhauser, L, Rummel, T, Rummel, K, Runov, A, Rust, N, Ryc, L, Salembier, P, Salewski, M, Sanchez, E, Satake, S, Satheeswaran, G, Schacht, J, Scharff, E, Schauer, F, Schilling, J, Schlisio, G, Schmid, K, Schmitt, J, Schmitz, O, Schneider, W, Schneider, M, Schneider, P, Schrittwieser, R, Schroder, T, Schroder, M, Schroeder, R, Schweer, B, Schworer, D, Scott, E, Shanahan, B, Sias, G, Sichta, P, Singer, M, Sinha, P, Siplia, S, Slaby, C, Sleczka, M, Smith, H, Smoniewski, J, Sonnendrucker, E, Spolaore, M, Spring, A, Stadler, R, Stanczak, D, Stange, T, Stepanov, I, Stephey, L, Stober, J, Stroth, U, Strumberger, E, Suzuki, C, Suzuki, Y, Svensson, J, Szabolics, T, Szepesi, T, Szucs, M, Tabares, F, Tamura, N, Tancetti, A, Tantos, C, Terry, J, Thienpondt, H, Thomsen, H, Thumm, M, Travere, J, Traverso, P, Tretter, J, Trier, E, Mora, H, Tsujimura, T, Turkin, Y, Tykhyi, A, Unterberg, B, van Eeten, P, van Milligen, B, van Schoor, M, Vano, L, Varoutis, S, Vecsei, M, Vela, L, Velasco, J, Vervier, M, Vianello, N, Viebke, H, Vilbrandt, R, Vogel, G, Vogt, N, Volkhausen, C, von Stechow, A, Wagner, F, Wang, E, Wang, H, Warmer, F, Wauters, T, Wegener, L, Wegner, T, Weir, G, Wenzel, U, White, A, Wilde, F, Wilms, F, Windisch, T, Winkler, M, Winter, A, Winters, V, Wolf, R, Wright, A, Wurden, G, Xanthopoulos, P, Xu, S, Yamada, H, Yamaguchi, H, Yokoyama, M, Yoshinuma, M, Yu, Q, Zamanov, M, Zanini, M, Zarnstorff, M, Zhang, D, Zhou, S, Zhu, J, Zhu, C, Zilker, M, Zocco, A, Zohm, H, Zoletnik, S, Zsuga, L, Fusion and Plasma Physics, Department of Applied Physics, National Institute for Fusion Science, Aalto-yliopisto, Aalto University, Science and Technology of Nuclear Fusion, Group Heemels, Control Systems Technology, and Turbulence in Fusion Plasmas

Subjects
Magnetic confinement, Nuclear and High Energy Physics, Technology, Materials science, Detachment, Nuclear engineering, Física::Física de partícules [Àrees temàtiques de la UPC], Imatges -- Processament, stellarator, Divertor, Image processing, Physics::Plasma Physics, divertor, Wendelstein 7-X, ddc:530, FIS/03 - FISICA DELLA MATERIA, Neoclassical optimization, Stellarators, Reactors de fusió, magnetic confinement, Enginyeria de la telecomunicació::Processament del senyal::Processament de la imatge i del senyal vídeo [Àrees temàtiques de la UPC], Condensed Matter Physics, ddc, Fusion reactors, Physics and Astronomy, detachment, neoclassical optimization, ddc:620, ddc:600, Paper, FEC 2020 Summaries and Overviews
Abstract

We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under Grant Agreement No. 633053. Peer Reviewed Article signat per 497 autors/es: Thomas Sunn Pedersen1,2,∗ , I. Abramovic3, P. Agostinetti4, M. Agredano Torres1, S. Äkäslompolo1, J. Alcuson Belloso1, P. Aleynikov1, K. Aleynikova1, M. Alhashimi1, A. Ali1, N. Allen5, A. Alonso6, G. Anda7, T. Andreeva1, C. Angioni8, A. Arkhipov8, A. Arnold1, W. Asad8, E. Ascasibar6, M.-H. Aumeunier9, K. Avramidis10, E. Aymerich11, S.-G. Baek3, J. Bähner1, A. Baillod12, M. Balden1, M. Balden8, J. Baldzuhn1, S. Ballinger3, M. Banduch1, S. Bannmann1, A. Banon Navarro8, A. Bañon Navarro ´ 1, T. Barbui13, C. Beidler1, C. Belafdil9, A. Bencze7, A. Benndorf1, M. Beurskens1, C. Biedermann1, O. Biletskyi14, B. Blackwell15, M. Blatzheim1, T. Bluhm1, D. Böckenhoff1, G. Bongiovi16, M. Borchardt1, D. Borodin17, J. Boscary8, H. Bosch1,18, T. Bosmann19, B. Böswirth8, L. Böttger1, A. Bottino8, S. Bozhenkov1, R. Brakel1, C. Brandt1, T. Bräuer1, H. Braune1, S. Brezinsek17, K. Brunner1, S. Buller1, R. Burhenn1, R. Bussiahn1, B. Buttenschön1, A. Buzás7, V. Bykov1, I. Calvo6, K. Camacho Mata1, I. Caminal20, B. Cannas11, A. Cappa6, A. Carls1, F. Carovani1, M. Carr21, D. Carralero6, B. Carvalho22, J. Casas20, D. Castano-Bardawil17, F. Castejon6, N. Chaudhary1, I. Chelis23, A. Chomiczewska24, J.W. Coenen13,17, M. Cole1, F. Cordella25, Y. Corre9, K. Crombe26, G. Cseh7, B. Csillag7, H. Damm1, C. Day10, M. de Baar27, E. De la Cal6, S. Degenkolbe1, A. Demby13, S. Denk3, C. Dhard1, A. Di Siena8,28, A. Dinklage12, T. Dittmar17, M. Dreval14, M. Drevlak1, P. Drewelow1, P. Drews17, D. Dunai7, E. Edlund3, F. Effenberg29, G. Ehrke1, M. Endler1, D.A. Ennis5, F.J. Escoto6, T. Estrada6, E. Fable8, N. Fahrenkamp1, A. Fanni11, J. Faustin1, J. Fellinger1, Y. Feng1, W. Figacz4, E. Flom13, O. Ford1, T. Fornal24, H. Frerichs13, S. Freundt1, G. Fuchert1, M. Fukuyama30, F. Füllenbach1, G. Gantenbein10, Y. Gao1, K. Garcia13, J.M. García Regaña6, I. García-Cortés6, J. Gaspar31, D.A. Gates29, J. Geiger1, B. Geiger13, L. Giudicotti32, A. González6, A. Goriaev26,33, D. Gradic1, M. Grahl1, J.P. Graves12, J. Green13, E. Grelier9, H. Greuner8, S. Groß1, H. Grote1, M. Groth34, M. Gruca24, O. Grulke1,35, M. Grün1, J. Guerrero Arnaiz1, S. Günter8, V. Haak1, M. Haas1, P. Hacker1, A. Hakola36, A. Hallenbert1, K. Hammond29, X. Han17,37, S.K. Hansen3, J.H. Harris38, H. Hartfuß1, D. Hartmann1, D. Hathiramani1, R. Hatzky8, J. Hawke39, S. Hegedus7, B. Hein8, B. Heinemann8, P. Helander12, S. Henneberg1, U. Hergenhahn8,40, C. Hidalgo6, F. Hindenlang8, M. Hirsch1, U. Höfel1, K.P. Hollfeld17, A. Holtz1, D. Hopf8, D. Höschen17, M. Houry9, J. Howard19, X. Huang41, M. Hubeny17, S. Hudson29, K. Ida9, Y. Igitkhanov10, V. Igochine8, S. Illy10, C. Ionita-Schrittwieser42, M. Isobe39, M. Jabłczynska ´ 24, S. Jablonski24, B. Jagielski1, M. Jakubowski1, A. Jansen van Vuuren1, J. Jelonnek10, F. Jenko8, F. Jenko8, T. Jensen35, H. Jenzsch1, P. Junghanns8, J. Kaczmarczyk24, J. Kallmeyer1, U. Kamionka1, M. Kandler8, S. Kasilov43, Y. Kazakov26, D. Kennedy1, A. Kharwandikar1, M. Khokhlov1, C. Kiefer8, C. Killer1, A. Kirschner17, R. Kleiber1, T. Klinger12, S. Klose1, J. Knauer1, A. Knieps17, F. Köchl44, G. Kocsis7, Ya.I. Kolesnichenko45, A. Könies1, R. König1, J. Kontula34, P. Kornejew1, J. Koschinsky, M.M. Kozulia14, A. Krämer-Flecken17, R. Krampitz1, M. Krause1, N. Krawczyk24, T. Kremeyer1, L. Krier10, D.M. Kriete5, M. Krychowiak1, I. Ksiazek46, M. Kubkowska24, M. Kuczynski1, G. Kühner1, A. Kumar15, T. Kurki-Suonio34, S. Kwak1, M. Landreman47, P.T. Lang8, A. Langenberg1, H.P. Laqua12, H. Laqua1, R. Laube1, S. Lazerson1, M. Lewerentz1, C. Li17, Y. Liang17, Ch. Linsmeier17, J. Lion1, A. Litnovsky17,48, S. Liu37, J. Lobsien1, J. Loizu12, J. Lore38, A. Lorenz1, U. Losada6, F. Louche26, R. Lunsford29, V. Lutsenko45, M. Machielsen12, F. Mackel8, J. Maisano-Brown3, O. Maj8, D. Makowski49, G. Manduchi50, E. Maragkoudakis6, O. Marchuk17, S. Marsen1, E. Martines4, J. Martinez-Fernandez6, M. Marushchenko1, S. Masuzaki41, D. Maurer5, M. Mayer8, K.J. McCarthy6, O. Mccormack4, P. McNeely1, H. Meister8, B. Mendelevitch8, S. Mendes1, A. Merlo1, A. Messian26, A. Mielczarek49, O. Mishchenko1, B. Missal1, R. Mitteau9, V.E. Moiseenko14, A. Mollen1, V. Moncada9, T. Mönnich1, T. Morisaki41, D. Moseev1, G. Motojima41, S. Mulas6, M. Mulsow1, M. Nagel1, D. Naujoks1, V. Naulin35, T. Neelis19, H. Neilson29, R. Neu8, O. Neubauer17, U. Neuner1, D. Nicolai17, S.K. Nielsen35, H. Niemann1, T. Nishiza1, T. Nishizawa1, T. Nishizawa8, C. Nührenberg1, R. Ochoukov8, J. Oelmann17, G. Offermanns17 K. Ogawa41, S. Okamura41, J. Ölmanns17, J. Ongena26, J. Oosterbeek1, M. Otte1, N. Pablant29, N. Panadero Alvarez6, N. Panadero Alvarez6, A. Pandey1, E. Pasch1, R. Pavlichenko14, A. Pavone1, E. Pawelec46, G. Pechstein1, G. Pelka24, V. Perseo1, B. Peterson41, D. Pilopp1, S. Pingel1, F. Pisano11, B. Plöckl8, G. Plunk1, P. Pölöskei1, B. Pompe2, A. Popov51, M. Porkolab3, J. Proll19, M.J. Pueschel19,27, M.-E. Puiatti52, A. Puig Sitjes1, F. Purps1, K. Rahbarnia1, M. Rasinski ´ 17, J. Rasmussen35, A. Reiman29, F. Reimold1, M. Reisner8, D. Reiter17, M. Richou9, R. Riedl8, J. Riemann1, K. Riße1, G. Roberg-Clark1, V. Rohde8, J. Romazanov17, D. Rondeshagen1, P. Rong1, L. Rudischhauser1, T. Rummel1, K. Rummel1, A. Runov1, N. Rust1, L. Ryc24, P. Salembier20, M. Salewski35, E. Sanchez6, S. Satake41, G. Satheeswaran17, J. Schacht1, E. Scharff1, F. Schauer8, J. Schilling1, G. Schlisio1, K. Schmid8, J. Schmitt5, O. Schmitz13, W. Schneider1, M. Schneider1, P. Schneider8, R. Schrittwieser42, T. Schröder1, M. Schröder1, R. Schroeder1, B. Schweer26, D. Schwörer1, E. Scott1, E. Scott8, B. Shanahan1, G. Sias11, P. Sichta29, M. Singer1, P. Sinha29, S. Sipliä34, C. Slaby1, M. Sleczka53, H. Smith1, J. Smoniewski54, E. Sonnendrücker8, M. Spolaore4, A. Spring1, R. Stadler8, D. Stanczak24, T. Stange1, I. Stepanov26, L. Stephey13, J. Stober8, U. Stroth8,55, E. Strumberger8, C. Suzuki41, Y. Suzuki41, J. Svensson1, T. Szabolics7, T. Szepesi7, M. Szücs7, F.L. Tabares6, N. Tamura41, A. Tancetti35, C. Tantos10, J. Terry3, H. Thienpondt6, H. Thomsen1, M. Thumm10, J.M. Travere9, P. Traverso5, J. Tretter8, E. Trier8, H. Trimino Mora1, T. Tsujimura41, Y. Turkin1, A. Tykhyi45, B. Unterberg17, P. van Eeten1, B.Ph. van Milligen6, M. van Schoor26, L. Vano1, S. Varoutis10, M. Vecsei7, L. Vela56, J.L. Velasco6, M. Vervier17, N. Vianello50, H. Viebke1, R. Vilbrandt1, G. Vogel8, N. Vogt1, C. Volkhausen1, A. von Stechow1, F. Wagner1, E. Wang17, H. Wang57, F. Warmer1, T. Wauters26, L. Wegener1, T. Wegner1, G. Weir1, U. Wenzel1, A. White3, F. Wilde1, F. Wilms1, T. Windisch1, M. Winkler1, A. Winter1, V. Winters1, R. Wolf118, A.M. Wright29, G.A. Wurden39, P. Xanthopoulos1, S. Xu17, H. Yamada58, H. Yamaguchi41, M. Yokoyama41, M. Yoshinuma41, Q. Yu8, M. Zamanov14, M. Zanini1, M. Zarnstorff29, D. Zhang1, S. Zhou17, J. Zhu1, C. Zhu29, M. Zilker8, A. Zocco1, H. Zohm8, S. Zoletnik7 and L. Zsuga7 // 1 Max Planck Institute for Plasma Physics, Garching and Greifswald, Germany: 2 University of Greifswald, Greifswald, Germany; 3 Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States of America; 4 Consorzio RFX, Corso Stati Uniti, 4-35127 Padova, Italy; 5 Auburn University, Auburn, AL 36849, United States of America; 6 CIEMAT, Avenida Complutense, 40, 28040 Madrid, Spain; 7 Center for Energy Research, Konkoly-Thegeut 29-33, 1121 Budapest, Hungary; 8 Max-Planck-Institute for Plasma Physics, Boltzmannstraße 2, 85748 Garching bei München, Germany; 9 CEA Cadarache, 13115 Saint-Paul-lez-Durance, France; 10 Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany; 11 University of Cagliari, Via Universita, 40, 09124 Cagliari, Italy; 12 École Polytechnique Fédérale de Lausanne, Swiss Plasma Center, CH-1015 Lausanne, Switzerland; 13 University of Wisconsin–Madison, Engineering Drive, Madison, WI 53706, United States of America; 14 Institute of Plasma Physics, National Science Center ‘Kharkiv Institute of Physics and Technology’, Kharkiv, Ukraine; 15 The Australian National University, Acton ACT 2601, Canberra, Australia; 16 Department of Engineering, University of Palermo, Viale delle Scienze, Edificio 6, Palermo, 90128, Italy; 17 Forschungszentrum Jülich GmbH, Institut für Energie-und Klimaforschung—Plasmaphysik, 52425 Jülich, Germany; 18 Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany; 19 Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands; 20 Universitat Politècnica de Catalunya. BarcelonaTech, C. Jordi Girona, 31, 08034 Barcelona, Spain; 21 Culham Center for Fusion Energy, Abingdon OX14 3EB, United Kingdom; 22 Instituto de Plasmas e Fusao Nuclear, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; 23 Department of Physics, National and Kapodistrian University of Athens, 15784 Athens, Greece; 24 Institute of Plasma Physics and Laser Microfusion, 23 Hery Str., 01-497 Warsaw, Poland; 25 ENEA—Centro Ricerche Frascati, Via Enrico Fermi, 45, 00044 Frascati RM, Italy; 26 Laboratory for Plasma Physics, LPP-ERM/KMS, TEC Partner, B-1000 Brussels, Belgium; 27 Dutch Institute for Fundamental Energy Research, PO Box 6336, 5600 HH Eindhoven, Netherlands; 28 University of Texas, Austin, TX, United States of America; 29 Princeton Plasma Physics Laboratory, Princeton, NJ 08543, United States of America; 30 Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395, Japan; 31 Aix-Marseille University, Jardin du Pharo, 58 Boulevard Charles Livon, 13007, Marseille, France; 32 Department of Physics and Astronomy, Padova University, Via Marzolo 8, 35131 Padova, Italy; 33 Department of Applied Physics, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent, Belgium; 34 Aalto University, 02150 Espoo, Finland; 35 Department of Physics, Technical University of Denmark, Anker Engelunds Vej, 2800 Kgs Lyngby, Denmark; 36 VTT Technical Research Center of Finland Ltd., PO Box 1000, FI-02044 VTT, Finland; 37 Institute of Plasma Physics, Chinese Academy of Sciences, 230031 Hefei, Anhui, China; 38 Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37830, United States of America; 39 Los Alamos National Laboratory, NM 87545, United States of America; 40 Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany; 41 National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki, Gifu Prefecture 509-5292, Japan; 42 Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria; 43 Graz University of Technology, Rechbauerstraße 12, 8010 GRAZ, Austria; 44 Austrian Academy of Science, Doktor-Ignaz-Seipel-Platz 2, 1010 Wien, Austria; 45 Institute for Nuclear Research, prospekt Nauky 47, Kyiv 03028, Ukraine; 46 University of Opole, plac Kopernika 11a, 45-001 Opole, Poland; 47 University of Maryland, Paint Branch Drive, College Park, MA 20742, United States of America; 48 National Research Nuclear University MEPhI, 115409 Moscow, Russian Federation; 49 Department of Microelectronics and Computer Science, Lodz University of Technology, Wolczanska 221/223, 90-924 Lodz, Poland; 50 Consiglio Nazionale delle Ricerche, Piazzale Aldo Moro, 7, 00185 Roma, Italy; 51 Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 26 Politekhnicheskaya, St Petersburg 194021, Russian Federation; 52 Istituto di Fisica del Plasma Piero Caldirola, Via Roberto Cozzi, 53, 20125 Milano, Italy; 53 University of Szczecin, 70-453, aleja Papieza Jana Pawła II 22A, Szczecin, Poland; 54 Lawrence University, 711 E Boldt Way, Appleton, WI 54911, United States of America; 55 Physik-Department E28, Technische Universität München, 85747 Garching, Germany; 56 Universidad Carlos III de Madrid, Av. de la Universidad, 30 Madrid, Spain; 57 Yale University, New Haven, CT 06520, United States of America; 58 University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chhiab 277-0882, Japan Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.a - Per a 2030, augmentar la cooperació internacional per tal de facilitar l’accés a la investigació i a les tecnolo­gies energètiques no contaminants, incloses les fonts d’energia renovables, l’eficiència energètica i les tecnologies de combustibles fòssils avançades i menys contaminants, i promoure la inversió en infraestructures energètiques i tecnologies d’energia no contaminant

Published
2022
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7. First neutral beam experiments on Wendelstein 7-X

Author

Uwe Hergenhahn, Christian Brandt, P. Valson, Wendelstein X Team, E. Pasch, M. W. Jakubowski, P. Pölöskei, Nikolai B. Marushchenko, Aleix Puig Sitjes, Kian Rahbarnia, Kunihiro Ogawa, Manfred Thumm, L. Vano, Bernd Heinemann, Wolfgang Leonhardt, Dirk Hartmann, D. Mellein, Jonathan Schilling, Jörg Weggen, R. Riedl, Tamara Andreeva, Daniel Papenfuß, Adnan Ali, C. Slaby, Rouven Lang, R. Schroeder, Samuel Lazerson, R. Burhenn, Michael Drevlak, Torsten Stange, Birger Buttenschoゆ, A. Spanier, John Jelonnek, R. C. Wolf, R. Koenig, S. Wadle, T. Wegner, Martina Huber, G. M. Weir, H. Thomsen, Kai Jakob Brunner, Yu Gao, G. Fuchert, P. McNeely, E. R. Scott, R. Bussiahn, P. Traverso, N. Chaudhary, Holger Niemann, Stefan Illy, Theo Scherer, H. Damm, Christian Hopf, S. A. Bozhenkov, Gerd Gantenbein, O. P. Ford, Andreas Langenberg, M. N. A. Beurskens, Simppa Äkäslompolo, Ulrich Neuner, Yuriy Turkin, Naoki Tamura, Andrea Pavone, J. P. Knauer, Niek den Harder, Thorsten Kobarg, N. A. Pablant, U. Hoefel, N. Rust, Philipp Nelde, Department of Applied Physics, Aalto-yliopisto, Aalto University, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Nuclear and High Energy Physics, Technology, Fast ions, Condensed Matter Physics, 01 natural sciences, Neutral beam, 010305 fluids & plasmas, law.invention, Nuclear physics, law, 0103 physical sciences, Energetic particles, Wendelstein 7-X, 010306 general physics, Fusion, ddc:600, Stellarator, Beam (structure)
Abstract

In the previous divertor campaign, the Wendelstein 7-X (W7-X) device injected 3.6 MW of neutral beam heating power allowing for the achievement of densities approaching 2 × 1020 m−3, and providing the first initial assessment of fast ion confinement in a drift optimized stellarator. The neutral beam injection (NBI) system on W7-X is comprised of two beam boxes with space for four radio frequency sources each. The 3.6 MW of heating reported in this work was achieved with two sources in the NI21 beam box. The effect of combined electron-cyclotron resonance heating (ECRH) and NBI was explored through a series of discharges varying both NBI and ECRH power. Discharges without ECRH saw a linear increase in the line-integrated plasma density, and strong peaking of the core density, over the discharge duration. The presence of 1 MW of ECRH power was found to be sufficient to control a continuous density rise during NBI operation. Simulations of fast ion wall loads were found to be consistent with experimental infrared camera images during operation. In general, NBI discharges were free from the presence of fast ion induced Alfvénic activity, consistent with low beam betas. These experiments provide data for future scenario development and initial assessment of fast-ion confinement in W7-X, a key topic of the project.

Published
2021

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

Author

V. Moncada, S. C. Liu, M. Winkler, P. Pölöskei, A. Tancetti, Naoki Tamura, H. Neilson, M. Krychowiak, Michael Drevlak, K. H. Schlüter, S. A. Henneberg, R. Vilbrandt, N. A. Pablant, M. Schröder, B. van Milligen, Bernd Heinemann, K. Rummel, Jonathan Schilling, Torsten Stange, G. Orozco, Christian Brandt, N. Krawczyk, Suguru Masuzaki, Yunfeng Liang, T. Estrada, Wolfgang Biel, J. H. Harris, B. Unterberg, M. Sleczka, M. Marushchenko, R. Lang, N. Rust, J. P. Kallmeyer, Laurie Stephey, P. Aleynikov, E. Blanco, Hans-Stephan Bosch, B. Buttenschön, D. Mellein, B. Shanahan, M. Vervier, M. Yokoyama, C. Suzuki, Seung Gyou Baek, A. Lücke, Felix Schauer, Ya. I. Kolesnichenko, V. Borsuk, Th. Rummel, B. Gonçalves, R. König, H. P. Laqua, G. Ehrke, K. J. McCarthy, Manfred Zilker, Venanzio Giannella, O. P. Ford, E. Flom, S. Murakami, Andreas Schlaich, P. Xanthopoulos, M. Zanini, E. Ascasíbar, C. Nührenberg, A. Carls, H. Viebke, Y. Feng, A. da Molin, H. Hunger, S. Paqay, Y. Wei, M. Blatzheim, M. W. Jakubowski, F. Köster, T. Wauters, J.C. Schmitt, M. Hubeny, P. van Eeten, H. Damm, Joris Fellinger, Gábor Cseh, Christoph Biedermann, G. Claps, L. Rudischhauser, R. Stadler, J. Mittelstaedt, Matteo Zuin, Z. Szökefalvi-Nagy, M. Knaup, Ch. Linsmeier, Francisco Castejón, J. P. Koschinsky, Bernardo B. Carvalho, L. Wegener, C. Guerard, J.M. Hernández Sánchez, B. Mendelevitch, A. Grosman, S. Pingel, Horacio Fernandes, M. Endler, N. Vianello, Jörg Schacht, Anett Spring, Yu Gao, V. Rohde, Samuel Lazerson, J.H. Matthew, W. Kasparek, R. Neu, R. Burhenn, N. Panadero, Jörg Weggen, P.A. Kurz, Walter H. Fietz, R. Schroeder, Andrea Pavone, G. Offermanns, Ryo Yasuhara, P. Sinha, Massimiliano Romé, José Luis Velasco, Carsten Killer, P. Drewelow, X. Han, T. Windisch, Nengchao Wang, Axel Könies, E.M. Edlund, K. P. Hollfeld, K. Aleynikova, Malte Henkel, Detlev Reiter, S. Brezinsek, Z. Huang, Heinz Grote, S. Langish, Matthias Otte, Alessandro Zocco, Daniel Papenfuß, G. Satheeswaran, Monika Kubkowska, S. Obermayer, G. A. Wurden, Carsten Lechte, F. Wagner, M. Gruca, H. Zhang, Olaf Neubauer, Peter Traverso, T. Ngo, V. Bykov, E. Sánchez, Matt Landreman, Dirk Naujoks, I. Vakulchyk, Andreas Langenberg, E. Wang, B. Hein, I. Ksiazek, S. Valet, Mark Cianciosa, G. Schlisio, Taina Kurki-Suonio, Oliver Schmitz, Adnan Ali, F. Reimold, Shinsuke Satake, Luis Vela Vela, C. Slaby, F. Remppel, David Gates, S. Schmuck, B. Roth, Zhirui Wang, Heinrich P. Laqua, F. Schluck, Olaf Grulke, S. Wadle, A. Runov, Manfred Thumm, Florian Effenberg, G. Fuchert, A. Vorköper, M. Banduch, Jonathan T. Green, J. Nührenberg, F. V. Chernyshev, H. Braune, Ewa Pawelec, David Maurer, A. Winter, A. Charl, Hiroshi Kasahara, T. Mizuuchi, D. Zhang, D. Höschen, J. Riemann, Thomas Klinger, W. Leonhardt, S. Sipliä, Katsumi Ida, T. Jesche, G. Pelka, U. Stridde, Riccardo Nocentini, Alexandra M. Freund, P. McNeely, A. Gogoleva, Victoria Winters, V. Szabó, Wolf-Dieter Schneider, D. A. Hartmann, Fabian Wilde, H. Schumacher, J. Howard, A. van Vuuren, J.L. Terry, M. Nagel, C. Hidalgo, Georg Kühner, S. Wolf, Boyd Blackwell, Michael Cole, Barbara Cannas, D. Rondeshagen, P. Hacker, Torsten Bluhm, J. Kacmarczyk, Kunihiro Ogawa, A. Zeitler, I. Yamada, P. Rong, Tamara Andreeva, Hiroshi Yamada, G. Anda, N. Panadero Alvarez, Wilfried Behr, F. Purps, H. Esteban, Dag Hathiramani, R. Bussiahn, David Ennis, A. H. Reiman, D. R. Mikkelsen, M. Borchardt, B. Israeli, M. Grahl, M. Losert, T. Dittmar, E. Pasch, U. Kamionka, Toru Ii Tsujimura, Gabriel G. Plunk, Felix Warmer, Jeremy Lore, F. Durodié, M. Balden, B.J. Peterson, J.P. Bähner, R. Schrittwieser, Morten Stejner, M.J. Cole, S. Zoletnik, Kian Rahbarnia, O. Marchuk, T. Bräuer, M. Hirsch, R. Riedl, W. Figacz, H. Trimino Mora, S. Degenkolbe, H. Greuner, B. Böswirth, B. Schweer, Dorothea Gradic, S. B. Ballinger, S. Ryosuke, B. Missal, Jiawu Zhu, J. H. E. Proll, M. Czerwinski, A. Cappa, B. Wiegel, J. Loizu Cisquella, Per Helander, Sehyun Kwak, S. Marsen, L. Carraro, T. Ilkei, D. Pilopp, Gábor Náfrádi, S. Récsei, M. Houry, A. de la Peña, Yu. Turkin, T.A. Scherer, T. Schröder, A. Galkowski, P. Drews, H. Frerichs, Benedikt Geiger, A. Krämer-Flecken, M. Dibon, L.-G. Böttger, A. Czarnecka, R. Krampitz, J. Wendorf, N. Chaudhary, T. Kremeyer, A. da Silva, R. Kleiber, R. Sakamoto, J.-M. Travere, I. Abramovic, T. Funaba, Andreas Meier, Fabio Pisano, Holger Niemann, Mirko Salewski, R. Brakel, M. Mayer, X. Huang, Stefan Illy, Ph. Mertens, Naoki Kenmochi, F. Köchl, Peter Lang, J. Geiger, Albert Mollén, A. Hölting, T. Barbui, M. Lennartz, T. Szabolics, Hayato Tsuchiya, S. Renard, A. Lorenz, J. Krom, C. D. Beidler, J. Cai, Andreas Dinklage, Anne White, Ye. O. Kazakov, P. Junghanns, W. Spiess, J. M. García Regaña, S. Elgeti, J. W. Coenen, Thomas Sunn Pedersen, C. Li, T. Mönnich, Miklos Porkolab, R. Laube, Burkhard Plaum, A. Benndorf, Michael Kramer, J. Ongena, J. Svensson, Dmitry Moseev, U. Wenzel, Chandra Prakash Dhard, S. Tulipán, M. C. Zarnstorff, M. Sibilia, A. von Stechow, G. M. Weir, H. Maaßberg, U. Höfel, P. Scholz, Alexey Mishchenko, R. C. Wolf, D. Carralero, G. Kocsis, Ivan Calvo, J. Tretter, Didier Chauvin, Y. Li, J. Boscary, A. Puig Sitjes, Fumimichi Sano, Andrey Samartsev, Tamás Szepesi, A. Kirschner, Dirk Nicolai, Francesco Cordella, M. Rack, A. Alonso, G. Czymek, E. R. Scott, M. E. Puiatti, Stefan Kragh Nielsen, M. Vergote, H. Schmitz, H. Jenzsch, Donald A. Spong, K. Czerski, A. Knieps, Arnold Lumsdaine, L. Ryć, M. N. A. Beurskens, Matthias F. Schneider, Simppa Äkäslompolo, Ulrich Neuner, V. Perseo, Jim-Felix Lobsien, Gerd Gantenbein, Roberto Guglielmo Citarella, L. Pacios Rodriguez, L. Vano, S. Bozhenkov, J. W. Oosterbeek, H. Röhlinger, J. P. Knauer, T. Nishizawa, A.H. Wright, M. Jia, A. Goriaev, H. Brand, D. Böckenhoff, H. M. Smith, J. P. Thomas, T. Fornal, J. Baldzuhn, D. Loesser, K. Risse, John Jelonnek, T. Wegner, S. Jablonski, Martina Huber, V. V. Lutsenko, S. Sereda, J. Ölmanns, Tomohiro Morisaki, H. Thomsen, J. A. Alcuson, P. Kornejew, J M Fontdecaba, Kai Jakob Brunner, A. Werner, T. Kobarg, European Commission, University of Greifswald, Max Planck Institute for Plasma Physics, Technical University of Denmark, Princeton University, National Institute for Fusion Science, CIEMAT, EURATOM HAS, Massachusetts Institute of Technology, University of Wisconsin-Madison, Research Center Julich, Australian National University, Eindhoven University of Technology, University of Cagliari, Consorzio RFX, Universidade de Lisboa, CEA Cadarache, St. Petersburg Scientific Centre, Oak Ridge National Laboratory, University of Salerno, ENEA Frascati Research Center, Institute of Plasma Physics and Laser Microfusion, University of Szczecin, University of Milano-Bicocca, Auburn University, Karlsruhe Institute of Technology, Universidad Carlos III de Madrid, University of Stuttgart, Austrian Academy of Sciences, National Academy of Sciences Ukraine, Technical University of Berlin, Opole University of Technology, Fusion and Plasma Physics, University of Maryland College Park, Consiglio Nazionale delle Ricerche (CNR), Kyoto University, Culham Centre for Fusion Energy, Physikalisch-Technische Bundesanstalt, Los Alamos National Laboratory, Department of Applied Physics, Aalto-yliopisto, and Aalto University

Subjects
Technology, CONFINEMENT, 01 natural sciences, impurities, 010305 fluids & plasmas, law.invention, ECR heating, Divertor, DENSITY LIMIT, law, Data_FILES, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), 004 Datenverarbeitung, Informatik, Physics, Glow discharge, Condensed Matter Physics, Content (measure theory), ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Electron temperature, Atomic physics, ddc:620, Stellarator, Impurities, Nuclear and High Energy Physics, Technology and Engineering, plasma performance, chemistry.chemical_element, Atmospheric-pressure plasma, PHYSICS, stellarator, Physics::Plasma Physics, NBI heating, 0103 physical sciences, divertor, 010306 general physics, Helium, Plasma performance, turbulence, Física, W7-X, Turbulence, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, chemistry, ddc:004, ddc:600, Energy (signal processing), SYSTEM
Abstract

The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor radius , and plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of with central electron temperatures were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to were reached with hydrogen pellet injection and helium gas fueling. Here, the ions are indirectly heated, and at a central density of a temperature of with was transiently accomplished, which corresponds to with a peak diamagnetic energy of and volume-averaged normalized plasma pressure . The routine access to high plasma densities was opened with boronization of the first wall. After boronization, the oxygen impurity content was reduced by a factor of 10, the carbon impurity content by a factor of 5. The reduced (edge) plasma radiation level gives routinely access to higher densities without radiation collapse, e.g. well above line integrated density and central temperatures at moderate ECRH power. Both X2 and O2 mode ECRH schemes were successfully applied. Core turbulence was measured with a phase contrast imaging diagnostic and suppression of turbulence during pellet injection was observed.

Published
2019
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10. Spark-Based Digital Factory Design

Author

Pölöskei, István

Abstract

Big data processing often uses the paradigm of parallelism by computing directly on top of the distributed data storage. The existing big data workflows unify the data processing practices to utilize the cloud’s native computational potentials to offer advanced machine learning and BI capabilities. Spark is an open-source massively parallel in-memory data processing framework, the current state-of-the-art. The primary approach is to break down the job into granular-level executed tasks, enabling parallelization. In the discussed case study, through IoT – cloud solutions, the plant data can be converted into an analyzable form to let the farther machine learning modules produce added value. To maximize the efficiency of the processing and accumulation, cloud-based components are introduced. Based on the data insights, the appropriate operative actions can be taken. The cost and performance optimization methods were also discussed in the study. Through achieving higher degree of digitalization, the control over the production increased.

Published
2022
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11. Validation of the BEAMS3D neutral beam deposition model on Wendelstein 7-X

Author

Tamara Andreeva, M. N. A. Beurskens, P. Valson, Simppa Äkäslompolo, G. Fuchert, Ulrich Neuner, E. R. Scott, Adnan Ali, Dirk Hartmann, Carolin Nuehrenberg, N. A. Pablant, J. P. Knauer, E. Pasch, Kian Rahbarnia, M. Hirsch, P. Pölöskei, R. C. Wolf, U. Hoefel, N. Chaudhary, Andrea Pavone, M. W. Jakubowski, Nikolai B. Marushchenko, Mike Machielsen, N. Rust, Philipp Nelde, Yuriy Turkin, Jonathan Schilling, Holger Niemann, P. Traverso, Samuel Lazerson, S. A. Bozhenkov, O. P. Ford, Uwe Hergenhahn, A. Spanier, Andreas Langenberg, H. Thomsen, L. Vano, Christian Brandt, G. M. Weir, Aleix Puig Sitjes, Tristan W. C. Neelis, David Pfefferlé, R. Koenig, Yu Gao, Jonathan Graves, Kai Jakob Brunner, P. McNeely, H. Damm, Torsten Stange, Max-Planck-Institut für Plasmaphysik, Department of Applied Physics, Swiss Federal Institute of Technology Lausanne, Eindhoven University of Technology, University of Western Australia, United States Department of Energy, Auburn University, University of Wisconsin-Madison, Aalto-yliopisto, Aalto University, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Nuclear and High Energy Physics, neutral beam, Cyclotron, Plasma confinement, 01 natural sciences, 010305 fluids & plasmas, law.invention, stellarator, beams3d, law, 0103 physical sciences, Deposition (phase transition), fast ions, 010306 general physics, Stellarator, Plasma density, validation, Physics, magnetic confinement, Magnetic confinement fusion, simulation, Condensed Matter Physics, BEAMS3D, magnetic confnement, Wendelstein 7-X, Atomic physics, Beam (structure)
Abstract

openaire: EC/H2020/633053/EU//EUROfusion The neutral beam deposition model in the BEAMS3D code is validated against neutral beam attenuation data from Wendelstein 7-X (W7-X). A set of experimental discharges where the neutral beam injection system of W7-X was utilized were reconstructed. These discharges scanned the magnetic configurations and plasma densities of W7-X. The equilibrium reconstructions were performed using STELLOPT which calculates three-dimensional self-consistent ideal magnetohydrodynamic equilibria and kinetic profiles. These reconstructions leveraged new capabilities to incorporate electron cyclotron emission and X-ray imaging diagnostics in the STELLOPT code. The reconstructed equilibria and profiles served as inputs for BEAMS3D calculations of neutral beam deposition in W7-X. It is found that if reconstructed kinetic profiles are utilized, good agreement between measured and simulated beam attenuation is found. As deposition models provide initial conditions for fast-ion slowing down calculations, this work provides a first steptowards validating our ability to predict fast ion confinement in stellarators.

Published
2020
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12. The Stl repressor from <italic>Staphylococcus aureus</italic> is an efficient inhibitor of the eukaryotic fruitfly dUTPase.

Author

Benedek, András, Pölöskei, István, Ozohanics, Olivér, Vékey, Károly, and Vértessy, Beáta G.

Subjects
DNA metabolism, URACIL, DNA, STAPHYLOCOCCAL diseases, EUKARYOTES
Abstract

DNA metabolism and repair is vital for the maintenance of genome integrity. Specific proteinaceous inhibitors of key factors in this process have high potential for deciphering pathways of DNA metabolism and repair. The dUTPase enzyme family is responsible for guarding against erroneous uracil incorporation into DNA. Here, we investigate whether the staphylococcal Stl repressor may interact with not only bacterial but also eukaryotic dUTPase. We provide experimental evidence for the formation of a strong complex between Stl and Drosophila melanogasterdUTPase. We also find that dUTPase activity is strongly diminished in this complex. Our results suggest that the dUTPase protein sequences involved in binding to Stl are at least partially conserved through evolution from bacteria to eukaryotes. [ABSTRACT FROM AUTHOR]

Published
2018
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13. Characterization of graphene-rubber nanocomposites: a review

Author

Sayfo, P., Pirityi, D.Z., and Pölöskei, K.

Abstract

Since its discovery in 2004, graphene has gained significant attention from both industry and academia. Its unique properties enable us to produce novel, enhanced polymer composites contributing to environmental and economic benefits. Graphene can improve the abrasion resistance of materials; thus, it can increase the service life of rubber tires. This present review discusses the testing of key properties of graphene and its elastomeric nanocomposites from a practical point of view. Graphene's layer thickness and its oxygen content are two key factors determining nano reinforcement's success. It is vital to monitor these properties both before and after mixing graphene with rubber to guarantee the high quality of the resulting nanocomposites. Ultimately, the distribution of nanoparticles within the matrix also plays a vital role in assuring strong reinforcement. Overall, we found that X-ray diffraction (XRD) spectroscopy can detect variation in all three aspects. Furthermore, Raman spectroscopy, transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS) can be used complementarily to support XRD findings.

Published
2023
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15. Use of reactive surfactants in basalt fiber reinforced polypropylene composites

Author

Matkó, Sz., Anna, P., Marosi, Gy., Szép, A., Keszei, S., Czigány, T., and Pölöskei, K.

Abstract

Basalt fibers, similarly to other silicate fibers, can be introduced into both thermoplastic and thermosetting polymer matrices. In this work some basalt fiber reinforced polypropylene composites were investigated. The fiber‐matrix adhesion was improved by commercial and non‐commercial maleic anhydride derivatives. The latter types, called reactive surfactants, were prepared in laboratory scale and the progress of the syntheses was determined by Raman microscopy. The additives allowed performing reactive interface modification during the compounding process. Due to the interface modification with the additives in low concentration the mechanical properties improved. The boundary layers on the surface of the reinforcing fibers were observed using scanning electron microscopy (SEM).

Published
2003
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16. Performance of the first neutral beam injector at the Wendelstein 7-X stellarator

Author

N. Rust, Thilo Romba, Simppa Äkäslompolo, R. Kairys, P. Rong, P. Pölöskei, A. Spanier, O. P. Ford, Christian Hopf, Bernd Heinemann, Dirk Hartmann, Niek den Harder, R. Riedl, Wendelstein X Team, R. C. Wolf, R. Schroeder, P. McNeely, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Materials science, Ion beam, Plasma parameters, Mechanical Engineering, Plasma, 01 natural sciences, 7. Clean energy, Neutral beam injection, 010305 fluids & plasmas, law.invention, Nuclear Energy and Engineering, law, 0103 physical sciences, Electron temperature, General Materials Science, Wendelstein 7-X, Atomic physics, 010306 general physics, Stellarator, Beam (structure), Civil and Structural Engineering
Abstract

The neutral beam injection (NBI) system at Wendelstein 7-X (W7-X) was operated for the first time in 2018. Detailed calorimetric measurements were carried out to accurately determine the energy flow within the NBI system and the injected power into the plasma. Of the electric energy put into the system (89± 6) % can be accounted for. The time-averaged injected NBI power is assessed to be Pinj ≈ (3.1 ± 0.8) MW for hydrogen injection with two positive ion sources at the maximum acceleration voltage of 54 kV. This corresponds to a conversion efficiency of the initially generated ion beam power to the injected neutral beam power of about 33%. The ionization in a plasma with an ion and electron temperature of Ti ≈ Te ≈ 1.3 keV and an electron density of ne ≈ 4 ·1019 m−3 is calorimetrically determined to be about 90%. The injected power is validated against beam emission spectroscopy applying Fast-Ion Dα analysis (FIDASIM). The inferred injected power leads to an energy confinement time of around τE ≈ 150 ms for pure NBI heating plasma experiments at W7-X with these heating and plasma parameters.

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17. Visible core spectroscopy at Wendelstein 7-X.

Author

Ford OP, Langenberg A, Romba T, Pölöskei P, Zanini M, Bannmann S, Gonda T, Ida K, Lopez Cansino R, Pablant N, de la Riva Villen J, Swee C, Yoshinuma M, Alonso A, Geiger B, Perseo V, and Viezzer E

Abstract

This paper presents an overview of recent hardware extensions and data analysis developments to the Wendelstein 7-X visible core spectroscopy systems. These include upgrades to prepare the in-vessel components for long-pulse operation, nine additional spectrometers, a new line of sight array for passive spectroscopy, and a coherence imaging charge exchange spectroscopy diagnostic. Progress in data analysis includes ion temperatures and densities from multiple impurity species, a statistical comparison with x-ray crystal spectrometer measurements, neutral density measurements from thermal passive Balmer-alpha emission, and a Bayesian analysis of active hydrogen emission, which is able to infer electron density and main ion temperature profiles., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/).)

Published
2024
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