Year: 2021
Type: article
Abstract: Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak1 is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X)2, a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator’s non-turbulent ‘neoclassical’ energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas3,4. The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible1,5. Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X, as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization.
Source: Nature
Authors: C. D. Beidler, H. M. Smith, A. Alonso, T. Andreeva, J. Baldzuhn, M. N. A. Beurskens, M. Borchardt, S. A. Bozhenkov, K. J. Brunner, H. Damm, M. Drevlak, O. P. Ford, G. Fuchert, J. Geiger, P. Helander, U. Hergenhahn, M. Hirsch, U. Höfel, Ye. O. Kazakov, R. Kleiber, M. Krychowiak, S. Kwak, A. Langenberg, H. P. Laqua, U. Neuner, N. A. Pablant, E. Pasch, A. Pavone, T. S. Pedersen, K. Rahbarnia, J. Schilling, E. R. Scott, T. Stange, J. Svensson, H. Thomsen, Y. Turkin, F. Warmer, R. C. Wolf, D. Zhang, the W7-X Team, I. Abramovic, S. Äkäslompolo, J. Alcusón, P. Aleynikov, K. Aleynikova, A. Ali, A. Alonso, G. Anda, E. Ascasibar, J. P. Bähner, S. G. Baek, M. Balden, M. Banduch, T. Barbui, W. Behr, A. Benndorf, C. Biedermann, W. Biel, B. Blackwell, E. Blanco, M. Blatzheim, S. Ballinger, T. Bluhm, D. Böckenhoff, B. Böswirth, L.-G. Böttger, V. Borsuk, J. Boscary, H.-S. Bosch, R. Brakel, H. Brand, C. Brandt, T. Bräuer, H. Braune, S. Brezinsek, K.-J. Brunner, R. Burhenn, R. Bussiahn, B. Buttenschön, V. Bykov, J. Cai, I. Calvo, B. Cannas, A. Cappa, A. Carls, L. Carraro, B. Carvalho, F. Castejon, A. Charl, N. Chaudhary, D. Chauvin, F. Chernyshev, M. Cianciosa, R. Citarella, G. Claps, J. Coenen, M. Cole, M. J. Cole, F. Cordella, G. Cseh, A. Czarnecka, K. Czerski, M. Czerwinski, G. Czymek, A. da Molin, A. da Silva, A. de la Pena, S. Degenkolbe, C. P. Dhard, M. Dibon, A. Dinklage, T. Dittmar, P. Drewelow, P. Drews, F. Durodie, E. Edlund, F. Effenberg, G. Ehrke, S. Elgeti, M. Endler, D. Ennis, H. Esteban, T. Estrada, J. Fellinger, Y. Feng, E. Flom, H. Fernandes, W. H. Fietz, W. Figacz, J. Fontdecaba, T. Fornal, H. Frerichs, A. Freund, T. Funaba, A. Galkowski, G. Gantenbein, Y. Gao, J. García Regaña, D. Gates, B. Geiger, V. Giannella, A. Gogoleva, B. Goncalves, A. Goriaev, D. Gradic, M. Grahl, J. Green, H. Greuner, A. Grosman, H. Grote, M. Gruca, O. Grulke, C. Guerard, P. Hacker, X. Han, J. H. Harris, D. Hartmann, D. Hathiramani, B. Hein, B. Heinemann, P. Helander, S. Henneberg, M. Henkel, U. Hergenhahn, J. Hernandez Sanchez, C. Hidalgo, K. P. Hollfeld, A. Hölting, D. Höschen, M. Houry, J. Howard, X. Huang, Z. Huang, M. Hubeny, M. Huber, H. Hunger, K. Ida, T. Ilkei, S. Illy, B. Israeli, S. Jablonski, M. Jakubowski, J. Jelonnek, H. Jenzsch, T. Jesche, M. Jia, P. Junghanns, J. Kacmarczyk, J.-P. Kallmeyer, U. Kamionka, H. Kasahara, W. Kasparek, N. Kenmochi, C. Killer, A. Kirschner, T. Klinger, J. Knauer, M. Knaup, A. Knieps, T. Kobarg, G. Kocsis, F. Köchl, Y. Kolesnichenko, A. Könies, R. König, P. Kornejew, J.-P. Koschinsky, F. Köster, M. Krämer, R. Krampitz, A. Krämer-Flecken, N. Krawczyk, T. Kremeyer, J. Krom, I. Ksiazek, M. Kubkowska, G. Kühner, T. Kurki-Suonio, P. A. Kurz, M. Landreman, P. Lang, R. Lang, S. Langish, H. Laqua, R. Laube, S. Lazerson, C. Lechte, M. Lennartz, W. Leonhardt, C. Li, C. Li, Y. Li, Y. Liang, C. Linsmeier, S. Liu, J.-F. Lobsien, D. Loesser, J. Loizu Cisquella, J. Lore, A. Lorenz, M. Losert, A. Lücke, A. Lumsdaine, V. Lutsenko, H. Maaßberg, O. Marchuk, J. H. Matthew, S. Marsen, M. Marushchenko, S. Masuzaki, D. Maurer, M. Mayer, K. McCarthy, P. McNeely, A. Meier, D. Mellein, B. Mendelevitch, P. Mertens, D. Mikkelsen, A. Mishchenko, B. Missal, J. Mittelstaedt, T. Mizuuchi, A. Mollen, V. Moncada, T. Mönnich, T. Morisaki, D. Moseev, S. Murakami, G. Náfrádi, M. Nagel, D. Naujoks, H. Neilson, R. Neu, O. Neubauer, T. Ngo, D. Nicolai, S. K. Nielsen, H. Niemann, T. Nishizawa, R. Nocentini, C. Nührenberg, J. Nührenberg, S. Obermayer, G. Offermanns, K. Ogawa, J. Ölmanns, J. Ongena, J. W. Oosterbeek, G. Orozco, M. Otte, L. Pacios Rodriguez, N. Panadero, N. Panadero Alvarez, D. Papenfuß, S. Paqay, E. Pawelec, T. S. Pedersen, G. Pelka, V. Perseo, B. Peterson, D. Pilopp, S. Pingel, F. Pisano, B. Plaum, G. Plunk, P. Pölöskei, M. Porkolab, J. Proll, M.-E. Puiatti, A. Puig Sitjes, F. Purps, M. Rack, S. Récsei, A. Reiman, F. Reimold, D. Reiter, F. Remppel, S. Renard, R. Riedl, J. Riemann, K. Risse, V. Rohde, H. Röhlinger, M. Romé, D. Rondeshagen, P. Rong, B. Roth, L. Rudischhauser, K. Rummel, T. Rummel, A. Runov, N. Rust, L. Ryc, S. Ryosuke, R. Sakamoto, M. Salewski, A. Samartsev, E. Sánchez, F. Sano, S. Satake, J. Schacht, G. Satheeswaran, F. Schauer, T. Scherer, A. Schlaich, G. Schlisio, F. Schluck, K.-H. Schlüter, J. Schmitt, H. Schmitz, O. Schmitz, S. Schmuck, M. Schneider, W. Schneider, P. Scholz, R. Schrittwieser, M. Schröder, T. Schröder, R. Schroeder, H. Schumacher, B. Schweer, S. Sereda, B. Shanahan, M. Sibilia, P. Sinha, S. Sipliä, C. Slaby, M. Sleczka, W. Spiess, D. A. Spong, A. Spring, R. Stadler, M. Stejner, L. Stephey, U. Stridde, C. Suzuki, V. Szabó, T. Szabolics, T. Szepesi, Z. Szökefalvi-Nagy, N. Tamura, A. Tancetti, J. Terry, J. Thomas, M. Thumm, J. M. Travere, P. Traverso, J. Tretter, H. Trimino Mora, H. Tsuchiya, T. Tsujimura, S. Tulipán, B. Unterberg, I. Vakulchyk, S. Valet, L. Vanó, P. van Eeten, B. van Milligen, A. J. van Vuuren, L. Vela, J.-L. Velasco, M. Vergote, M. Vervier, N. Vianello, H. Viebke, R. Vilbrandt, A. von Stechow, A. Vorköper, S. Wadle, F. Wagner, E. Wang, N. Wang, Z. Wang, T. Wauters, L. Wegener, J. Weggen, T. Wegner, Y. Wei, G. Weir, J. Wendorf, U. Wenzel, A. Werner, A. White, B. Wiegel, F. Wilde, T. Windisch, M. Winkler, A. Winter, V. Winters, S. Wolf, R. C. Wolf, A. Wright, G. Wurden, P. Xanthopoulos, H. Yamada, I. Yamada, R. Yasuhara, M. Yokoyama, M. Zanini, M. Zarnstorff, A. Zeitler, H. Zhang, J. Zhu, M. Zilker, A. Zocco, S. Zoletnik, M. Zuin
Institutions: Max Planck Institute for Plasma Physics - Greifswald, Max Planck Institute for Plasma Physics, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Fritz Haber Institute of the Max Planck Society, Royal Military Academy, Princeton Plasma Physics Laboratory, HUN-REN Wigner Research Centre for Physics, Massachusetts Institute of Technology, University of Wisconsin–Madison, Forschungszentrum Jülich, Australian National University, Technical University of Denmark, Eindhoven University of Technology, University of Cagliari, Instituto de Plasmas e Fusão Nuclear, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Cadarache, Ioffe Institute, Oak Ridge National Laboratory, University of Salerno, National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA Frascati Research Centre, Institute of Plasma Physics and Laser Microfusion, University of Szczecin, University of Milano-Bicocca, Auburn University, Karlsruhe Institute of Technology, National Institute for Fusion Science, Universidad Carlos III de Madrid, University of Stuttgart, Universität Greifswald, Austrian Academy of Sciences, Institute for Nuclear Research, Technische Universität Berlin, University of Opole, Aalto University, University of Maryland, College Park, Physikalisch-Technische Bundesanstalt, Kyoto University, Institute of Plasma Physics, Culham Centre for Fusion Energy, Los Alamos National Laboratory
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $11,390
OpenAlex ID: W3190034652