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1,095 results on '"Laqua, H."'

1. ICRF plasma production in gas mixtures in the Uragan-2M stellarator

Author

Kovtun, Yu.V., Moiseenko, V.E., Lozin, A.V., Kozulya, M.M., Pavlichenko, R.O., Zamanov, N.V., Shapoval, A.N., Bondarenko, V.N., Baron, D.I., Maznichenko, S.M., Korovin, V.B., Kramskoy, E.D., Siusko, Y.V., Romanov, V.S., Martseniuk, Yu.P., Krasiuk, A.Yu., Listopad, V.M., Garkusha, I.E., Alonso, A., Dinklage, A., Hartmann, D., Kazakov, Ye., Laqua, H., Ongena, J., Stange, T., and Wauters, T.

Published
2023
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2. Plasma Production in ICRF in the Uragan-2M Stellarator in Hydrogen–Helium Gas Mixture

Author

Moiseenko, V. E., Kovtun, Yu. V., Lozin, A. V., Pavlichenko, R. O., Shapoval, A. N., Grigor’eva, L. I., Kozulya, M. M., Maznichenko, S. M., Korovin, V. B., Kramskoy, E. D., Zamanov, N. V., Siusko, Y. V., Baron, D. I., Krasiuk, A. Yu., Romanov, V. S., Garkusha, I. E., Wauters, T., Alonso, A., Brakel, R., Dinklage, A., Hartmann, D., Kazakov, Ye., Laqua, H., Ongena, J., and Stange, T.

Published
2022
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3. Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., Höfel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., and Zhang, D.

Published
2021
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4. Development of the 174 GHz collective Thomson scattering diagnostics at Wendelstein 7-X

Author

Ponomarenko, S., Moseev, D., Stange, T., Krier, L., Stordiau, P., Braune, H., Gantenbein, G, Jelonnek, J., Kuleshov, A., Laqua, H. P., Lechte, C., Marsen, S., Nielsen, S. K., Oosterbeek, J. W., Plaum, B., Ragona, R., Rasmussen, J., Ruess, T., Salewski, M, Thumm, M., Zimmermann, J., Ponomarenko, S., Moseev, D., Stange, T., Krier, L., Stordiau, P., Braune, H., Gantenbein, G, Jelonnek, J., Kuleshov, A., Laqua, H. P., Lechte, C., Marsen, S., Nielsen, S. K., Oosterbeek, J. W., Plaum, B., Ragona, R., Rasmussen, J., Ruess, T., Salewski, M, Thumm, M., and Zimmermann, J.

Abstract

In this paper, we present the design and commissioning results of the upgraded collective Thomson scattering diagnostic at the Wendelstein 7-X stellarator. The diagnostic has a new radiometer designed to operate between the second and third harmonics of the electron cyclotron emission from the plasma at 171-177 GHz, where the emission background has a minimum and is of order 10-100 eV. It allows us to receive the scattered electromagnetic field with a significantly improved signal-to-noise ratio and extends the set of possible scattering geometries compared to the case of the original instrument operated at 140 GHz. The elements of the diagnostic are a narrowband notch filter and a frequency stabilized probing gyrotron that will allow measuring scattered radiation spectra very close to the probing frequency. Here, we characterize the microwave components applied to the radiometer and demonstrate the performance of the complete system that was achieved during the latest experimental campaign, OP2.1.

Published
2024

6. The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

Author

Laqua H. P., Avramidis K. A., Braune H., Chelis I., Gantenbein G., Illy S., Ioannidis Z., Jelonnek J., Jin J., Krier L., Lechte C., Leggieri A., Legrand F., Marsen S., Moseev D., Oosterbeek H., Rzesnicki T., Ruess T., Stange T., Thumm M., Tigelis I., and Wolf R. C.

Subjects
Physics, QC1-999
Abstract

The existing ECRH system at W7-X consists of 10 gyrotrons, with output power levels ranging from 0.6 MW up to 1.0 MW each at a frequency of 140 GHz, quasi-optical transmission lines and microwave launchers at the plasma vessel. Compared to other large fusion experiments, W7-X has a relatively low power-to-volume ratio. However high heating power is particularly necessary for achieving high plasma beta values, where the improved confinement of fast ions, one of the optimization criteria of W7-X, can be examined. It is therefore necessary to expand the ECRH systems in several consecutive steps. It is planned to increase the number of gyrotron positions from 10 to 12 and at the same time to evolve the gyrotron output power in several development steps from 1 MW to nominal 1.5 MW and, finally, up to 2 MW. At the same time, the transmission lines will also be upgraded for 2 MW operation. A special effort is also made to improve the reliability of the system by the fast control system.

Published
2023
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8. An effective sub-quadratic scaling atomic-orbital reformulation of the scaled opposite-spin RI-CC2 ground-state model using Cholesky-decomposed densities and an attenuated Coulomb metric.

Author

Sacchetta, F., Graf, D., Laqua, H., Ambroise, M. A., Kussmann, J., Dreuw, A., and Ochsenfeld, C.

Subjects
DENSITY matrices, LINEAR algebra, MOLECULAR orbitals, DENSITY, ATOMS
Abstract

An atomic-orbital reformulation of the Laplace-transformed scaled opposite-spin (SOS) coupled cluster singles and doubles (CC2) model within the resolution of the identity (RI) approximation (SOS-RI-CC2) is presented that extends its applicability to molecules with several hundreds of atoms and triple-zeta basis sets. We exploit sparse linear algebra and an attenuated Coulomb metric to decrease the disk space demands and the computational efforts. In this way, an effective sub-quadratic computational scaling is achieved with our ω-SOS-CDD-RI-CC2 model. Moreover, Cholesky decomposition of the ground-state one-electron density matrix reduces the prefactor, allowing for an early crossover with the molecular orbital formulation. The accuracy and performance of the presented method are investigated for various molecular systems. [ABSTRACT FROM AUTHOR]

Published
2022
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9. Progress in High Power Gyrotron Development Projects at KIT

Author

Gantenbein, G., primary, Avramidis, K., additional, Ell, B., additional, Delpech, L., additional, Feuerstein, L., additional, Illy, S., additional, Jelonnek, J., additional, Jin, J., additional, Krier, L., additional, Laqua, H. P., additional, Ruess, T., additional, Rzesnicki, T., additional, Stanculovic, S., additional, and Thumm, M., additional

Published
2023
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10. Observation of impurity accumulation and its compatibility with high plasma performance in W7-X

Author

Zhang, D, primary, Buttenschön, B, additional, Jablonski, S, additional, Kubkowska, M, additional, Ford, O, additional, Alcusón, J A, additional, Beidler, C D, additional, Burhenn, R, additional, Beurskens, M N A, additional, Langenberg, A, additional, Pablant, N, additional, Reimold, F, additional, Rahbarnia, K, additional, Smith, H M, additional, Wegner, Th, additional, Wurden, G, additional, Bozhenkov, S A, additional, Feng, Y, additional, Brunner, K J, additional, Fuchert, G, additional, Gao, Y, additional, Geiger, J, additional, Giannone, L, additional, Höfel, U, additional, Hirsch, M, additional, Huang, Z, additional, Knauer, J, additional, Kremeyer, T, additional, Krychowiak, M, additional, Kwak, S, additional, Laqua, H P, additional, Laube, R, additional, Neuner, U, additional, Pasch, E, additional, Pavone, A, additional, von Stechow, A, additional, Svensson, J, additional, and Thomsen, H, additional

Published
2023
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11. ICRF plasma production at hydrogen minority regime in LHD

Author

Kovtun, Yu.V., primary, Kasahara, H., additional, Moiseenko, V.E., additional, Kamio, S., additional, Seki, T., additional, Saito, K., additional, Seki, R., additional, Dinklage, A., additional, Hartmann, D., additional, Laqua, H., additional, Stange, T., additional, Lazerson, S., additional, Alonso, A., additional, Wauters, T., additional, Kazakov, Ye., additional, Ongena, J., additional, and Garkusha, I.E., additional

Published
2023
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12. NON-RESONANT MICROWAVE DISCHARGE START-UP IN HELIOTRON J

Author

Kovtun, Y., Nagasaki, K., Kobayashi, S., Minami, T., Kado, S., Ohshima, S., Nakamura, Y., Ishizawa, A., Konoshima, S., Mizuuchi, T., Okada, H., Laqua, H., Stange, T., and https://orcid.org/0000-0003-4154-1455

Abstract

The non-resonant microwave discharge in strong magnetic fields was investigated in Heliotron J under the condition, ωce/ωMW > 1 (ωce and ωMW are the angular electron cyclotron frequency and the angular microwave frequency, respectively). Following the production of a non-resonant microwave discharge plasma, it undergoes several phases in sequence: breakdown and formation of pre-ionized plasma, increase in linear and nonlinear phases of plasma density, and quasi-stationary stage. Several modes of non-resonant microwave discharge were investigated. In the power-scanning mode in non-resonant microwave discharge, a higher plasma density than that in the constant-power mode is achieved. The maximum average density achieved in the experiments is substantially greater than the critical density for O-wave (ordinary waves) 7.45 ⸱1016 m -3 and can reach the value of 2.5⸱10 18 m -3. .

Published
2023

15. Measurements and controls implementation for WEST

Author

Moreau, P., Bucalossi, J., Missirlian, M., Samaille, F., Courtois, X., Gil, C., Lotte, P., Meyer, O., Nardon, E., Nouailletas, R., Ravenel, N., Travere, J.M., Alarcon, T., Antusch, S., Aumeunier, M.H., Barjat, P., Belsare, S., Bernard, J.M., Bhandarkar, M., Bottereau, C., Bourdelle, C., Brémond, S., Camenen, Y., Chaudhari, V., Chavda, C., Chernyshova, M., Clairet, F., Colnel, J., Czarski, T., Choi, M., Colledani, G., Corre, Y., Daniel, R., Davis, D., Dejarnac, R., Devynck, P., Dhongde, J., Douai, D., Elbeze, D., Escarguel, A., Fenzi, C., Figacz, W., Guangwu, Z., Giacalone, J.C., Guirlet, R., Gunn, J., Hacquin, S., Hao, X., Harris, J.H., Hoang, G.T., Houry, M., Imbeaux, F., Jablonski, S., Jardin, A., Joshi, H., Kasprowicz, G., Klepper, C.C., Kowalska-Strzeciwilk, E., Kubkowska, M., Kumar, A., Kumar, V., Kumari, P., Laqua, H., Le-Luyer, A., Lee, W., Lewerentz, M., Lyu, B., Malard, P., Manenc, L., Mansuri, I., Marandet, Y., Masand, H., Mazon, D., Molina, D., Moureau, G., Nam, Y., Park, H., Pascal, J.Y., Patel, K., Patel, M., Pozniak, K., Radloff, D., Ranjan, S., Rapson, C., Raupp, G., Rieth, M., Sabot, R., Santraine, B., Sestac, D., Sharma, M., Shen, J., Signoret, J., Soni, J., Spring, A., Spuig, P., Sugandhi, R., Treuterrer, W., Tsitrone, E., Varshney, S., Vartanian, S., Volpe, D., Wang, F.D., Werner, A., Yun, G., Zabolotny, W., and Zhao, W.

Published
2017
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16. Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

Author

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, Pedersen T. S., Abramovic I., Agostinetti P., Torres M. A., Akaslompolo S., Belloso J. A., 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. -H., Avramidis K., Aymerich E., Baek S. -G., Bahner J., Baillod A., Balden M., Baldzuhn J., Ballinger S., Banduch M., Bannmann S., Navarro A. B., 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. C., 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. W., 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. A., Escoto F. J., 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. M. G., Garcia-Cortes I., Gaspar J., Gates D. A., Geiger J., Geiger B., Giudicotti L., Gonzalez A., Goriaev A., Gradic D., Grahl M., Graves J. P., Green J., Grelier E., Greuner H., Gross S., Grote H., Groth M., Gruca M., Grulke O., Grun M., Arnaiz J. G., Gunter S., Haak V., Haas M., Hacker P., Hakola A., Hallenbert A., Hammond K., Han X., Hansen S. K., Harris J. H., 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. P., 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. J., 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 Ya. I., Konies A., Konig R., Kontula J., Kornejew P., Koschinsky J., Kozulia M. M., Kramer-Flecken A., Krampitz R., Krause M., Krawczyk N., Kremeyer T., Krier L., Kriete D. M., Krychowiak M., Ksiazek I., Kubkowska M., Kuczynski M., Kuhner G., Kumar A., Kurki-Suonio T., Kwak S., Landreman M., Lang P. T., Langenberg A., Laqua H. P., Laqua H., Laube R., Lazerson S., Lewerentz M., Li C., Liang Y., Linsmeier Ch., 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. J., McCormack O., McNeely P., Meister H., Mendelevitch B., Mendes S., Merlo A., Messian A., Mielczarek A., Mishchenko O., Missal B., Mitteau R., Moiseenko V. E., 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. K., 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. P., 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. J., Puiatti M. -E., Sitjes A. P., 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. L., Tamura N., Tancetti A., Tantos C., Terry J., Thienpondt H., Thomsen H., Thumm M., Travere J. M., Traverso P., Tretter J., Trier E., Mora H. T., Tsujimura T., Turkin Y., Tykhyi A., Unterberg B., van Eeten P., van Milligen B. Ph., van Schoor M., Vano L., Varoutis S., Vecsei M., Vela L., Velasco J. L., 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. M., Wurden G. A., 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., 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, Pedersen T. S., Abramovic I., Agostinetti P., Torres M. A., Akaslompolo S., Belloso J. A., 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. -H., Avramidis K., Aymerich E., Baek S. -G., Bahner J., Baillod A., Balden M., Baldzuhn J., Ballinger S., Banduch M., Bannmann S., Navarro A. B., 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. C., 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. W., 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. A., Escoto F. J., 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. M. G., Garcia-Cortes I., Gaspar J., Gates D. A., Geiger J., Geiger B., Giudicotti L., Gonzalez A., Goriaev A., Gradic D., Grahl M., Graves J. P., Green J., Grelier E., Greuner H., Gross S., Grote H., Groth M., Gruca M., Grulke O., Grun M., Arnaiz J. G., Gunter S., Haak V., Haas M., Hacker P., Hakola A., Hallenbert A., Hammond K., Han X., Hansen S. K., Harris J. H., 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. P., 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. J., 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 Ya. I., Konies A., Konig R., Kontula J., Kornejew P., Koschinsky J., Kozulia M. M., Kramer-Flecken A., Krampitz R., Krause M., Krawczyk N., Kremeyer T., Krier L., Kriete D. M., Krychowiak M., Ksiazek I., Kubkowska M., Kuczynski M., Kuhner G., Kumar A., Kurki-Suonio T., Kwak S., Landreman M., Lang P. T., Langenberg A., Laqua H. P., Laqua H., Laube R., Lazerson S., Lewerentz M., Li C., Liang Y., Linsmeier Ch., 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. J., McCormack O., McNeely P., Meister H., Mendelevitch B., Mendes S., Merlo A., Messian A., Mielczarek A., Mishchenko O., Missal B., Mitteau R., Moiseenko V. E., 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. K., 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. P., 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. J., Puiatti M. -E., Sitjes A. P., 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. L., Tamura N., Tancetti A., Tantos C., Terry J., Thienpondt H., Thomsen H., Thumm M., Travere J. M., Traverso P., Tretter J., Trier E., Mora H. T., Tsujimura T., Turkin Y., Tykhyi A., Unterberg B., van Eeten P., van Milligen B. Ph., van Schoor M., Vano L., Varoutis S., Vecsei M., Vela L., Velasco J. L., 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. M., Wurden G. A., 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., and Zsuga L.

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.

Published
2022

17. Magnetic configuration effects on the Wendelstein 7-X stellarator

Author

Dinklage, A., Beidler, C. D., Helander, P., Fuchert, G., Maaßberg, H., Rahbarnia, K., Sunn Pedersen, T., Turkin, Y., Wolf, R. C., Alonso, A., Andreeva, T., Blackwell, B., Bozhenkov, S., Buttenschön, B., Czarnecka, A., Effenberg, F., Feng, Y., Geiger, J., Hirsch, M., Höfel, U., Jakubowski, M., Klinger, T., Knauer, J., Kocsis, G., Krämer-Flecken, A., Kubkowska, M., Langenberg, A., Laqua, H. P., Marushchenko, N., Mollén, A., Neuner, U., Niemann, H., Pasch, E., Pablant, N., Rudischhauser, L., Smith, H. M., Schmitz, O., Stange, T., Szepesi, T., Weir, G., Windisch, T., Wurden, G. A., Zhang, D., and and the W7-X Team

Published
2018
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18. Inhibition of parametric decay in heating microwave beams during fluctuations of the density profile in the edge island of Wendelstein 7-X

Author

Tancetti, A., Nielsen, S. K., Rasmussen, J., Moseev, D., Stange, T., Marsen, S., Vecséi, M., Killer, C., Wurden, G. A., Jensen, T., Stejner, M., Anda, G., Dunai, D., Zoletnik, S., Rahbarnia, K., Brandt, C., Thomsen, H., Hirsch, M., Hoefel, U., Chaudhary, N., Winters, V., Kornejew, P., Harris, J., Laqua, H. P., Tancetti, A., Nielsen, S. K., Rasmussen, J., Moseev, D., Stange, T., Marsen, S., Vecséi, M., Killer, C., Wurden, G. A., Jensen, T., Stejner, M., Anda, G., Dunai, D., Zoletnik, S., Rahbarnia, K., Brandt, C., Thomsen, H., Hirsch, M., Hoefel, U., Chaudhary, N., Winters, V., Kornejew, P., Harris, J., and Laqua, H. P.

Abstract

Experimental evidence of parametric decay instability (PDI) is observed in the Wendelstein 7-X stellarator, when high-power microwave beams cross a stationary magnetic island at the plasma edge. Here, trapping and build-up of upper hybrid waves within a density bump (measured within the island by alkali beam emission spectroscopy) is responsible for the reduction of the instability power threshold below the maximum gyrotron power. In this paper, we provide the first experimental evidence of the connection between the trapping mechanism in the island density bump and excitation of PDI-related signals. We show correlations of periodic crashes in the PDI-related signals with quasi-continuous fluctuations at the plasma edge, which, additionally, cause a flattening of the density profile in the island. We demonstrate that flattening of the experimental density profiles can suppress the trapping mechanism and inhibit the low-threshold PDI. PDI on the edge island could alter the power deposition profile and reduce the efficiency of the electron cyclotron resonance heating system, simultaneously posing a serious threat to the optimal operation of microwave-based diagnostics and plasma-facing components.

Published
2023

19. Operational Characteristics of the 175-GHz Continuous-Wave Clinotron

Author

Ponomarenko, S., Braune, H., Khutoryan, E., Kishko, S., Kovshov, Y., Kuleshov, A., Laqua, H. P., Moseev, D., Stange, T., and Vlasenko, S.

Abstract

The operational characteristics of a watt-level water-cooled 175-GHz continuous-wave (CW) clinotron are studied experimentally and discussed in this article. The oscillator is designed to work either in the broad frequency range (161–175 GHz) and moderate output power (10–200 mW) or in a high-power regime, which has a maximum power of 0.85 W at 174.6 GHz and up to 1.2 W at 171.4 GHz. The radiation power and the frequency can be tuned by changing an acceleration voltage and a beam current. The studies are focused on the long-term drifts of the output power and frequency during a free-running operation of the clinotron. In particular, the influence of a beam current and a cooling water temperature on the frequency is considered and the contribution of both effects is discussed. The maximal variations of a power level and an oscillation frequency observed within 1 h are less than $3\times 10^{-{2}}$ and $5\times 10^{-{5}}$ , respectively.

Published
2023
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20. Inhibition of parametric decay in heating microwave beams during fluctuations of the density profile in the edge island of Wendelstein 7-X

Author

Tancetti, A, primary, Nielsen, S K, additional, Rasmussen, J, additional, Moseev, D, additional, Stange, T, additional, Marsen, S, additional, Vecséi, M, additional, Killer, C, additional, Wurden, G A, additional, Jensen, T, additional, Stejner, M, additional, Anda, G, additional, Dunai, D, additional, Zoletnik, S, additional, Rahbarnia, K, additional, Brandt, C, additional, Thomsen, H, additional, Hirsch, M, additional, Hoefel, U, additional, Chaudhary, N, additional, Winters, V, additional, Kornejew, P, additional, Harris, J, additional, and Laqua, H P, additional

Published
2022
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21. The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

Author

Laqua, H., Avramidis, K., Braune, H., Chelis, I., Gantenbein, G., Illy, S., Ioannidis, Z., Jelonnek, J., Jin, J., Krier, L., Lechte, C., Leggieri, A., Legrand, F., Marsen, S., Moseev, D., https://orcid.org/0000-0001-7955-8565, Oosterbeek, J., Rzesnicki, T., Ruess, T., Stange, T., https://orcid.org/0000-0003-4154-1455, Thumm, M., Tigelis, I., Wolf, R., https://orcid.org/0000-0002-2606-5289, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Published
2023

22. Short-pulse frequency stabilization of a MW-class ECRH gyrotron at W7-X for CTS diagnostic

Author

W7-X Team, Krier, L., Avramidis, K. A., Braune, H., Gantenbein, G., Illy, S., Jelonnek, J., Laqua, H. P., Marsen, S., Moseev, D., Noke, F., Ruess, T., Stange, T., Thumm, M., and Wolf, R. C.

Subjects
Technology, ddc:600
Abstract

At the Wendelstein 7-X stellarator, a 174 GHz Collective Thomson Scattering (CTS) diagnostic will be implemented. One of the 140 GHz Electron Cyclotron Resonance Heating (ECRH) gyrotrons will be operated at around 174 GHz in a higher cavity mode, using it as source for the CTS mm-wave probing beam. To prevent any damage to the CTS receiver, a notch filter cuts out the high-power gyrotron signal at the entrance of the receiver. The bandwidth of the gyrotron signal determines the notch filter bandwidth. First proof-of-principle experiments on frequency stabilization were conducted on W7-X ECRH gyrotrons employing Phase-Locked Loop techniques. The gyrotron output frequency was controlled with the accelerating voltage, which is applied between the anode and cathode of the gyrotron diode-type Magnetron Injection Gun. Frequency stabilization experiments with 10 ms pulses were conducted at the gyrotron nominal frequency of 140 GHz as well as at 174 GHz. It is concluded that the gyrotron frequency could be stabilized for at least 3 ms at 140 GHz and 8 ms at 174 GHz. In the frequency spectrum, a clear main peak of the gyrotron frequency at 140 GHz with a full -15 dB linewidth of below 500 Hz was achieved.

Published
2023
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23. Numerical analyses of CVD diamond windows in high power microwave applications

Author

Aiello, Gaetano, Meier, Andreas, Scherer, Theo, Laqua, H. P., Schreck, Sabine, and Strauss, Dirk

Subjects
ddc:620, Engineering & allied operations
Abstract

Nuclear fusion reactors require electron cyclotron heating and current drive (EC H&CD) systems for plasma heating and stabilization. Chemical vapor deposition (CVD) polycrystalline diamond windows on both the torus and gyrotron sides of the reactors act as confinement and/or vacuum boundaries allowing the transmission of high-power microwave beams. For example, the beam power scenarios of 1.5 MW and 2 MW are the current targets considered respectively in Wendelstein 7-X and European DEMO fusion machines. In this work, with reference to both reactors, the numerical analyses required to verify the thermal and structural performance of the windows are discussed. Experimental measurements of loss tangent in diamond provided inputs for the numerical analyses. Sensitivity studies of the windows with respect to loss tangent and other parameters were also carried out to check the temperature reserve margins of the design.

Published
2023
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24. MISTRAL campaign in support of W7-X long pulse operation

Author

Oosterbeek, J., Stern, M., Braune, H., Ewert, K., Hirsch, M., https://orcid.org/0000-0002-7120-6087, Hollmann, F., Killinger, A., Laqua, H., Maquet, P., Marsen, S., Martinez-Garcia, V., Moseev, D., https://orcid.org/0000-0001-7955-8565, Noke, F., Pak, S., Reintrog, A., Stange, T., https://orcid.org/0000-0003-4154-1455, Wolf, R., https://orcid.org/0000-0002-2606-5289, Zubieta-Lupo, R., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Published
2023

25. The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

Author

W7-X Team, Laqua, H. P., Avramidis, K. A., Braune, H., Chelis, I., Gantenbein, G., Illy, S., Ioannidis, Z., Jelonnek, J., Jin, J., Krier, L., Lechte, C., Leggieri, A., Legrand, F., Marsen, S., Moseev, D., Oosterbeek, H., Rzesnicki, T., Ruess, T., Stange, T., Thumm, M., Tigelis, I., Wolf, R. C., Poli, E., Liu, Y., and Udintsev, V.

Subjects
Technology, ddc:600, W7-X, ECRH
Abstract

The existing ECRH system at W7-X consists of 10 gyrotrons, with output power levels ranging from 0.6 MW up to 1.0 MW each at a frequency of 140 GHz, quasi-optical transmission lines and microwave launchers at the plasma vessel. Compared to other large fusion experiments, W7-X has a relatively low power-to-volume ratio. However high heating power is particularly necessary for achieving high plasma beta values, where the improved confinement of fast ions, one of the optimization criteria of W7-X, can be examined. It is therefore necessary to expand the ECRH systems in several consecutive steps. It is planned to increase the number of gyrotron positions from 10 to 12 and at the same time to evolve the gyrotron output power in several development steps from 1 MW to nominal 1.5 MW and, finally, up to 2 MW. At the same time, the transmission lines will also be upgraded for 2 MW operation. A special effort is also made to improve the reliability of the system by the fast control system.

Published
2023

26. Plasma Production in ICRF in the Uragan-2M Stellarator in Hydrogen–Helium Gas Mixture

Author

Moiseyenko, Volodymyr, Kovtun, Yu. V., Lozin, A. V., Pavlichenko, R. O., Shapoval, A. N., Grigor’eva, L. I., Kozulya, M. M., Maznichenko, S. M., Korovin, V. B., Kramskoy, E. D., Zamanov, N. V., Siusko, Y. V., Baron, D. I., Krasiuk, A. Yu., Romanov, V. S., Garkusha, I. E., Wauters, T., Alonso, A., Brakel, R., Dinklage, A., Hartmann, D., Kazakov, Ye., Laqua, H., Ongena, J., Stange, T., Moiseyenko, Volodymyr, Kovtun, Yu. V., Lozin, A. V., Pavlichenko, R. O., Shapoval, A. N., Grigor’eva, L. I., Kozulya, M. M., Maznichenko, S. M., Korovin, V. B., Kramskoy, E. D., Zamanov, N. V., Siusko, Y. V., Baron, D. I., Krasiuk, A. Yu., Romanov, V. S., Garkusha, I. E., Wauters, T., Alonso, A., Brakel, R., Dinklage, A., Hartmann, D., Kazakov, Ye., Laqua, H., Ongena, J., and Stange, T.

Published
2022
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27. Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

Author

Pedersen, Thomas Sunn, Abramovic, I., Agostinetti, P., Torres, M. Agredano, Äkäslompolo, S., Belloso, J. Alcuson, 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. H., Avramidis, K., Aymerich, E., Baek, S. G., Bähner, J., Baillod, A., Balden, M., Baldzuhn, J., Ballinger, S., Banduch, M., Bannmann, S., Navarro, A. Bañón, Barbui, T., Beidler, C., Belafdil, C., Bencze, A., Benndorf, A., Beurskens, M., Biedermann, C., Biletskyi, O., Blackwell, B., Blatzheim, M., Bluhm, T., Böckenhoff, D., Bongiovi, G., Borchardt, M., Borodin, D., Boscary, J., Bosch, H., Bosmann, T., Böswirth, B., Böttger, L., Bottino, A., Bozhenkov, S., Brakel, R., Brandt, C., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K., Buller, S., Burhenn, R., Bussiahn, R., Buttenschön, B., Buzás, A., Bykov, V., Calvo, I., Mata, K. Camacho, 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. W., 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. A., Escoto, F. J., 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., Füllenbach, F., Gantenbein, G., Gao, Y., Garcia, K., Regaña, J. M.García, García-Cortés, I., Gaspar, J., Gates, D. A., Geiger, J., Geiger, B., Giudicotti, L., González, A., Goriaev, A., Gradic, D., Grahl, M., Graves, J. P., Green, J., Grelier, E., Greuner, H., Groß, S., Grote, H., Groth, M., Gruca, M., Grulke, O., Grün, M., Arnaiz, J. Guerrero, Günter, S., Haak, V., Haas, M., Hacker, P., Hakola, A., Hallenbert, A., Hammond, K., Han, X., Hansen, S. K., Harris, J. H., 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., Höfel, U., Hollfeld, K. P., Holtz, A., Hopf, D., Höschen, D., Houry, M., Howard, J., Huang, X., Hubeny, M., Hudson, S., Ida, K., Igitkhanov, Y., Igochine, V., Illy, S., Ionita-Schrittwieser, C., Isobe, M., Jabłczynska, M., Jablonski, S., Jagielski, B., Jakubowski, M., van Vuuren, A. Jansen, 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., Köchl, F., Kocsis, G., Kolesnichenko, Ya I., Könies, A., König, R., Kontula, J., Kornejew, P., Koschinsky, J., Kozulia, M. M., Krämer-Flecken, A., Krampitz, R., Krause, M., Krawczyk, N., Kremeyer, T., Krier, L., Kriete, D. M., Krychowiak, M., Ksiazek, I., Kubkowska, M., Kuczynski, M., Kühner, G., Kumar, A., Kurki-Suonio, T., Kwak, S., Landreman, M., Lang, P. T., Langenberg, A., Laqua, H., Laube, R., Lazerson, S., Lewerentz, M., Li, C., Liang, Y., Linsmeier, Ch, 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. J., McCormack, O., McNeely, P., Meister, H., Mendelevitch, B., Mendes, S., Merlo, A., Messian, A., Mielczarek, A., Mishchenko, O., Missal, B., Mitteau, R., Moiseenko, V. E., Mollen, A., Moncada, V., Mönnich, 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. K., Niemann, H., Nishiza, T., Nishizawa, T., Nührenberg, C., Ochoukov, R., Oelmann, J., Offermanns, G., Ogawa, K., Okamura, S., Ölmanns, J., Ongena, J., Oosterbeek, J., Otte, M., Pablant, N., Alvarez, N. Panadero, Pandey, A., Pasch, E., Pavlichenko, R., Pavone, A., Pawelec, E., Pechstein, G., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plöckl, B., Plunk, G., Pölöskei, P., Pompe, B., Popov, A., Porkolab, M., Proll, J., Pueschel, M. J., Puiatti, M. E., Sitjes, A. Puig, 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., Schröder, T., Schröder, M., Schroeder, R., Schweer, B., Schwörer, D., Scott, E., Shanahan, B., Sias, G., Sichta, P., Singer, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Smith, H., Smoniewski, J., Sonnendrücker, 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., Szücs, M., Tabarés, F. L., Tamura, N., Tancetti, A., Tantos, C., Terry, J., Thienpondt, H., Thomsen, H., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trier, E., Mora, H. Trimino, Tsujimura, T., Turkin, Y., Tykhyi, A., Unterberg, B., van Eeten, P., van Milligen, B. Ph, van Schoor, M., Vano, L., Varoutis, S., Vecsei, M., Vela, L., Velasco, J. L., 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. M., Wurden, G. A., 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., Pedersen, Thomas Sunn, Abramovic, I., Agostinetti, P., Torres, M. Agredano, Äkäslompolo, S., Belloso, J. Alcuson, 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. H., Avramidis, K., Aymerich, E., Baek, S. G., Bähner, J., Baillod, A., Balden, M., Baldzuhn, J., Ballinger, S., Banduch, M., Bannmann, S., Navarro, A. Bañón, Barbui, T., Beidler, C., Belafdil, C., Bencze, A., Benndorf, A., Beurskens, M., Biedermann, C., Biletskyi, O., Blackwell, B., Blatzheim, M., Bluhm, T., Böckenhoff, D., Bongiovi, G., Borchardt, M., Borodin, D., Boscary, J., Bosch, H., Bosmann, T., Böswirth, B., Böttger, L., Bottino, A., Bozhenkov, S., Brakel, R., Brandt, C., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K., Buller, S., Burhenn, R., Bussiahn, R., Buttenschön, B., Buzás, A., Bykov, V., Calvo, I., Mata, K. Camacho, 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. W., 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. A., Escoto, F. J., 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., Füllenbach, F., Gantenbein, G., Gao, Y., Garcia, K., Regaña, J. M.García, García-Cortés, I., Gaspar, J., Gates, D. A., Geiger, J., Geiger, B., Giudicotti, L., González, A., Goriaev, A., Gradic, D., Grahl, M., Graves, J. P., Green, J., Grelier, E., Greuner, H., Groß, S., Grote, H., Groth, M., Gruca, M., Grulke, O., Grün, M., Arnaiz, J. Guerrero, Günter, S., Haak, V., Haas, M., Hacker, P., Hakola, A., Hallenbert, A., Hammond, K., Han, X., Hansen, S. K., Harris, J. H., 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., Höfel, U., Hollfeld, K. P., Holtz, A., Hopf, D., Höschen, D., Houry, M., Howard, J., Huang, X., Hubeny, M., Hudson, S., Ida, K., Igitkhanov, Y., Igochine, V., Illy, S., Ionita-Schrittwieser, C., Isobe, M., Jabłczynska, M., Jablonski, S., Jagielski, B., Jakubowski, M., van Vuuren, A. Jansen, 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., Köchl, F., Kocsis, G., Kolesnichenko, Ya I., Könies, A., König, R., Kontula, J., Kornejew, P., Koschinsky, J., Kozulia, M. M., Krämer-Flecken, A., Krampitz, R., Krause, M., Krawczyk, N., Kremeyer, T., Krier, L., Kriete, D. M., Krychowiak, M., Ksiazek, I., Kubkowska, M., Kuczynski, M., Kühner, G., Kumar, A., Kurki-Suonio, T., Kwak, S., Landreman, M., Lang, P. T., Langenberg, A., Laqua, H., Laube, R., Lazerson, S., Lewerentz, M., Li, C., Liang, Y., Linsmeier, Ch, 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. J., McCormack, O., McNeely, P., Meister, H., Mendelevitch, B., Mendes, S., Merlo, A., Messian, A., Mielczarek, A., Mishchenko, O., Missal, B., Mitteau, R., Moiseenko, V. E., Mollen, A., Moncada, V., Mönnich, 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. K., Niemann, H., Nishiza, T., Nishizawa, T., Nührenberg, C., Ochoukov, R., Oelmann, J., Offermanns, G., Ogawa, K., Okamura, S., Ölmanns, J., Ongena, J., Oosterbeek, J., Otte, M., Pablant, N., Alvarez, N. Panadero, Pandey, A., Pasch, E., Pavlichenko, R., Pavone, A., Pawelec, E., Pechstein, G., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plöckl, B., Plunk, G., Pölöskei, P., Pompe, B., Popov, A., Porkolab, M., Proll, J., Pueschel, M. J., Puiatti, M. E., Sitjes, A. Puig, 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., Schröder, T., Schröder, M., Schroeder, R., Schweer, B., Schwörer, D., Scott, E., Shanahan, B., Sias, G., Sichta, P., Singer, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Smith, H., Smoniewski, J., Sonnendrücker, 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., Szücs, M., Tabarés, F. L., Tamura, N., Tancetti, A., Tantos, C., Terry, J., Thienpondt, H., Thomsen, H., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trier, E., Mora, H. Trimino, Tsujimura, T., Turkin, Y., Tykhyi, A., Unterberg, B., van Eeten, P., van Milligen, B. Ph, van Schoor, M., Vano, L., Varoutis, S., Vecsei, M., Vela, L., Velasco, J. L., 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. M., Wurden, G. A., 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., and Zsuga, L.

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.

Published
2022

28. Confinement in electron heated plasmas in Wendelstein 7-X and ASDEX Upgrade; the necessity to control turbulent transport

Author

Beurskens, M. N. A., Angioni, C., Bozhenkov, S. A., Ford, O., Kiefer, C., Xanthopoulos, P., Turkin, Y., Alcuson, J. A., Baehner, J. P., Beidler, C., Birkenmeier, G., Fable, E., Fuchert, G., Geiger, B., Grulke, O., Hirsch, M., Jakubowski, M., Laqua, H. P., Langenberg, A., Lazerson, S., Pablant, N., Reisner, M., Schneider, P., Scott, E. R., Stange, T., von Stechow, A., Stober, J., Stroth, U., Wegner, Th., Weir, G., Zhang, D., Zocco, A., Wolf, R. C., Zohm, H., Beurskens, M. N. A., Angioni, C., Bozhenkov, S. A., Ford, O., Kiefer, C., Xanthopoulos, P., Turkin, Y., Alcuson, J. A., Baehner, J. P., Beidler, C., Birkenmeier, G., Fable, E., Fuchert, G., Geiger, B., Grulke, O., Hirsch, M., Jakubowski, M., Laqua, H. P., Langenberg, A., Lazerson, S., Pablant, N., Reisner, M., Schneider, P., Scott, E. R., Stange, T., von Stechow, A., Stober, J., Stroth, U., Wegner, Th., Weir, G., Zhang, D., Zocco, A., Wolf, R. C., and Zohm, H.

Abstract

In electron (cyclotron) heated plasmas, in both ASDEX Upgrade (L-mode) and Wendelstein 7-X, clamping of the ion temperature occurs at Ti ∼ 1.5 keV independent of magnetic configuration. The ions in such plasmas are heated through the energy exchange power as ne2(Te-Ti)/Te3/2, which offers a broad ion heating profile, similar to that offered by alpha heating in future thermonuclear fusion reactors. However, the predominant electron heating may put an additional constraint on the ion heat transport, as the ratio Te/Ti > 1 can exacerbates ITG/TEM core turbulence. Therefore, in practical terms the strongly 'stiff' core transport translates into Ti-clamping in electron heated plasmas. Due to this clamping, electron heated L-mode scenarios, with standard gas fueling, in either tokamaks or stellarators may struggle to reach high normalized ion temperature gradients required in a compact fusion reactor. The comparison shows that core heat transport in neoclassically optimized stellarators is driven by the same mechanisms as in tokamaks. The absence of a strong H-mode temperature edge pedestal in stellarators, sofar (which, like in tokamaks, could lift the clamped temperature-gradients in the core), puts a strong requirement on reliable and sustainable core turbulence suppression techniques in stellarators.

Published
2022

29. Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma

Author

Tancetti, A., Nielsen, S. K., Rasmussen, J., Gusakov, E. Z., Popov, A. Yu, Moseev, D., Stange, T., Senstius, M. G., Killer, C., Vecséi, M., Jensen, T., Zanini, M., Abramovic, I., Stejner, M., Anda, G., Dunai, D., Zoletnik, S., Laqua, H. P., Tancetti, A., Nielsen, S. K., Rasmussen, J., Gusakov, E. Z., Popov, A. Yu, Moseev, D., Stange, T., Senstius, M. G., Killer, C., Vecséi, M., Jensen, T., Zanini, M., Abramovic, I., Stejner, M., Anda, G., Dunai, D., Zoletnik, S., and Laqua, H. P.

Abstract

We present novel experimental evidence of parametric decay instability of microwave beams in the plasma edge of the Wendelstein 7-X stellarator. We propose that the instability is sustained by trapping of only one daughter wave in the non-monotonic density profile measured with high spatial resolution within a stationary magnetic island. The power levels and spectral shapes of the detected microwave signal are reproduced by numerical modelling and a theoretical power threshold is predicted around 300 kW, comparable with observations. We predict a fraction of power drained by daughter waves around 4% in the experiments, potentially increasing above 50% for more hollow edge density profiles. Such absorption levels could significantly reduce the efficiency of the microwave heating and current-drive system in tokamaks and stellarators.

Published
2022

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

Author

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

Published
2022
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34. Plasma Production in ICRF in the Uragan-2M Stellarator in Hydrogen– Helium Gas Mixture

Author

Moiseenko, V., Kovtun, Y., Lozin, A., Pavlichenko, R., Shapoval, A., Grigoreva, L., Kozulya, M., Maznichenko, S., Korovin, V., Kramskoy, E., Zamanov, N., Siusko, Y., Baron, D., Krasiuk, A., Romanov, V., Garkusha, I., Wauters, T., Alonso, A., Brakel, R., Dinklage, A., https://orcid.org/0000-0002-5815-8463, Hartmann, D., https://orcid.org/0000-0002-3511-6500, Kazakov, Y., Laqua, H., Ongena, J., Stange, T., https://orcid.org/0000-0003-4154-1455, and Uragan-M Team

Subjects
Nuclear and High Energy Physics, Nuclear Energy and Engineering
Published
2022

35. Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

Author

Bucalossi, J., Achard, J., Agullo, O., Alarcon, T., Allegretti, L., Ancher, H., Antar, G., Antusch, S., Anzallo, V., Arnas, C., Arranger, D., Artaud, J. F., Aumeunier, M. H., Baek, S. G., Bai, X., Balbin, J., Balorin, C., Barbui, T., Barbuti, A., Barlerin, J., Basiuk, V., Batal, T., Baulaigue, O., Bec, A., Bécoulet, M., Benoit, E., Benard, E., Benard, J. M., Bertelli, N., Bertrand, E., Beyer, P., Bielecki, J., Bienvenu, P., Bisson, R., Bobkov, V., Bodner, G., Bottereau, C., Bouchand, C., Bouquey, F., Bourdelle, C., Bourg, J., Brezinsek, S., Brochard, F., Brun, C., Bruno, V., Bufferand, H., Bureau, A., Burles, S., Camenen, Y., Cantone, B., Caprin, E., Carpentier, S., Caulier, G., Chanet, N., Chellai, O., Chen, Y., Chernyshova, M., Chmielewski, P., Choe, W., Chomiczewska, A., Ciraolo, G., Clairet, F., Coenen, J., Colas, L., Colledani, G., Colnel, J., Coquillat, P., Corbel, E., Corre, Y., Costea, S., Courtois, X., Czarski, T., Daniel, R., Daumas, J., De Combarieu, M., Temmerman, G., De, De Vries, P., Dechelle, C., Deguara, F., Dejarnac, R., Delaplanche, J. M., Delgado-Aparicio, L. F., Delmas, E., Delpech, L., Desgranges, C., Devynck, P., Di Genova, S., Diab, R., Diallo, A., Diez, M., Dif-Pradalier, G., Dimitrova, M., Ding, B., Dittmar, T., Doceul, L., Domenes, M., Douai, D., Dougnac, H., Duan, X., Dubus, L., Dumas, N., Dumont, R., Durand, F., Durif, A., Durocher, A., Durodié, F., Ekedahl, A., Elbeze, D., Ertmer, S., Escarguel, A., Escourbiac, F., Ezato, K., Faisse, F., Faure, N., Fedorczak, N., Fejoz, P., Fenzi-Bonizec, C., Ferlay, F., Firdaouss, M., Fleury, L., Flouquet, D., Gallo, A., Gao, Y., Garbet, X., Garcia, J., Gardarein, J. L., Gargiulo, L., Garibaldi, P., Garitta, S., Gaspar, J., Gauthier, E., Gavila, P., Gazzotti, S., Gely, F., Geynet, M., Gharafi, S., Ghendrih, P., Giacalone, I., Gil, C., Ginoux, S., Girard, S., Giroux, E., Giruzzi, G., Goletto, C., Goniche, M., Gray, T., Grelier, E., Greuner, H., Grigore, E., Grisolia, C., Grosjean, A., Grosman, A., Guibert, D., Guilhem, D., Guillemaut, C., Guillermin, B., Guirlet, R., Gunn, J. P., Gunsu, Y., Gyergyek, T., Hakola, A., Harris, J., Hatchressian, J. C., Helou, W., Hennequin, P., Hernandez, C., Hill, K., Hillairet, J., Hirai, T., Hoang, G. T., Houry, M., Hutter, T., Imbeaux, F., Imbert, N., Ivanova-Stanik, I., Jalageas, R., Jardin, A., Jaubert, L., Jiolat, G., Jonas, A., Joubert, P., Kirschner, A., Klepper, C., Komm, M., Koubiti, M., Kovacic, J., Kozeiha, M., Krieger, K., Krol, K., Lacroix, B., Laguardia, L., Lamaison, V., Laqua, H., Lau, C., Lausenaz, Y., Lé, R., Le Bohec, M., Lefevre, N., Lemoine, N., Lerche, E., Lewerentz, M., Li, Y., Li, M., Liang, A., Linczuk, P., Linsmeier, C., Lipa, M., Litaudon, X., Liu, X., Llorens, J., Loarer, T., Loarte, A., Loewenhoff, T., Lombard, G., Lore, J., Lorenzetto, P., Lotte, P., Lozano, M., Lu, B., Lunsford, R., Luo, G., Magaud, P., Maget, P., Mahieu, J. F., Maini, P., Malard, P., Malinowski, K., Manas, P., Manenc, L., Marandet, Y., Marechal, J. L., Marek, S., Martin, C., Martin, E., Martinez, A., Martino, P., Mazon, D., Messina, P., Meunier, L., Midou, D., Mineo, Y., Missilian, M., Mitteau, R., Mitu, B., Mollard, P., Moncada, V., Mondiere, T., Morales, J., Moreau, M., Moreau, P., Moudden, Y., Moureau, G., Mouyon, D., Muraglia, M., Nagy, A., Nakano, T., Nardon, E., Neff, A., Nespoli, F., Nichols, J., Nicollet, S., Nouailletas, R., Ono, M., Ostuni, V., Parish, C., Park, H., Parrat, H., Pascal, J. Y., Pégourié, B., Pellissier, F. P., Peneliau, Y., Peret, M., Peysson, Y., Pignoly, E., Pintsuk, G., Pitts, R., Pocheau, C., Portafaix, C., Poulos, M., Prochet, P., Puig Sitjes, A., Rasinski, M., Raup, G., Regal-Mezin, X., Reux, C., Riccardi, B., Rice, J., Richou, M., Rigollet, F., Roche, H., Romazanov, J., Ruset, C., Sabot, R., Saille, A., Sakamoto, R., Salmon, T., Samaille, F., Santagiustina, A., Santraine, B., Sarazin, Y., Serre, E., Shin, H., Shiraiwai, S., Signoret, Ja., Signoret, Je., Simonin, A., Skalli Fettachi, O., Song, Y., Spring, A., Spuig, P., Sridhar, S., Stratton, B., Talatizi, C., Tamain, P., Tatali, R., Téna, M., Torre, A., Toulouse, L., Travère, J. M., Treutterer, W., Tsitrone, E., Unterberg, E., Urbanczyk, G., Van Eester, D., Van Rooij, G., Vartanian, S., Verger, J. M., Vermare, L., Vézinet, D., Vignal, N., Vincent, B., Vives, S., Volpe, D., Wallace, G., Wang, E., Wang, L., Wang, Yi., Wang, Yo., Wauters, T., Wirth, B., Wirtz, M., Wojenski, A., Wright, J., Xu, M., Yang, Q., Yang, H., Zago, B., Zagorski, Zhang, B., Zhang, X., Zou, X., Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and 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)

Subjects
Nuclear and High Energy Physics, Tokamak, Materials science, WEST, Nuclear engineering, Phase (waves), chemistry.chemical_element, Tungsten, law.invention, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], law, ITER, divertor, DEMO, Engineering & allied operations, nuclear fusion, Superconductivity, [PHYS]Physics [physics], Divertor, RF power amplifier, magnetic confinement, Plasma, Condensed Matter Physics, chemistry, Heat flux, ddc:620, tokamak physics
Abstract

WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described.

Published
2022

36. Microwave stray radiation losses in vacuum windows

Author

Oosterbeek, J. W., Stern, M., Braune, H., Ewert, K., Hirsch, M., Hollmann, F., Laqua, H. P., Marsen, S., Meier, A., Moseev, D., Noke, F., Reintrog, A., Stange, T., Wolf, R. C., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Loss tangent, Nuclear Energy and Engineering, Vacuum window losses, Mechanical Engineering, Microwave stray radiation, General Materials Science, ddc:620, Engineering & allied operations, W7-X, Civil and Structural Engineering, ECRH, Dielectric losses
Abstract

Vacuum windows are required in magnetically confined fusion experiments to provide possibilities to observe the plasma in a wide range of electromagnetic wavelengths. The window disk consists of a dielectric, e.g. Fused Silica (SiO$_2$), Sapphire or Chemically Vapourised Diamond (CVD). As electromagnetic waves pass through the disk, a fraction of the beam power is dissipated resulting in a temperature increase of the disk. In Electron Cyclotron Waves (ECW) heated plasmas the dissipation in the window disk can be very high. The computation of dielectric losses for a collimated beam with known incidence angle, polarisation and loss tangent (measure for the intrinsic dielectric loss) is well established. However, the dielectric losses in diagnostic windows mostly result from microwave stray radiation, which results from a modest, but inevitable, fraction of non-absorbed ECW. This fraction diffuses in the vessel by many reflections into rays with random k-vector and with random polarisation. In this work the thermal load on the window disk by microwave stray radiation is assessed. The load by a collimated beam is studied as a function of incidence angle and polarisation allowing to average over a distribution of incident rays. An experiment was commissioned measuring the loss tangent of a number of commercially available SiO$_2$ disks at low power in an open resonator, and subsequently measuring the dielectric heating of these disks at high power stray radiation using the facility ’MISTRAL’ at Wendelstein-7X. The experimental results are compared to modelling and it is demonstrated that, in the parameter range considered, single-pass fractional absorption may be applied while taking a safety margin that arises from the minima and maxima due to multiple reflections.

Published
2022
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40. Confinement in electron heated plasmas in Wendelstein 7-X and ASDEX Upgrade; the necessity to control turbulent transport

Author

W7-X Team, Beurskens, M. N. A., Angioni, C., Bozhenkov, S. A., Ford, O., Kiefer, C., Xanthopoulos, P., Turkin, Y., Alcusón, J. A., Baehner, J. P., Beidler, C., Birkenmeier, G., Fable, E., Fuchert, G., Geiger, B., Grulke, O., Hirsch, M., Jakubowski, M., Laqua, H. P., Langenberg, A., Lazerson, S., Pablant, N., Reisner, M., Schneider, P., Scott, E. R., Stange, T., Stechow, A. von, Stober, J., Stroth, U., Wegner, Th., Weir, G., Zhang, D., Zocco, A., Wolf, R. C., Zohm, H., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Technology, Nuclear and High Energy Physics, Turbulent transport, Materials science, Turbulence, Ion temperature clamping, Plasma, Electron, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Nuclear physics, Electron heating, ASDEX Upgrade, Physics::Plasma Physics, 0103 physical sciences, Stellarator transport, Wendelstein 7-X, ddc:620, 010306 general physics, ddc:600
Abstract

In electron (cyclotron) heated plasmas, in both ASDEX Upgrade (L-mode) and Wendelstein 7-X, clamping of the ion temperature occurs at T i ∼ 1.5 keV independent of magnetic configuration. The ions in such plasmas are heated through the energy exchange power as n e 2 ( T e − T i ) / T e 3 / 2 , which offers a broad ion heating profile, similar to that offered by alpha heating in future thermonuclear fusion reactors. However, the predominant electron heating may put an additional constraint on the ion heat transport, as the ratio T e/T i > 1 can exacerbates ITG/TEM core turbulence. Therefore, in practical terms the strongly ‘stiff’ core transport translates into T i-clamping in electron heated plasmas. Due to this clamping, electron heated L-mode scenarios, with standard gas fueling, in either tokamaks or stellarators may struggle to reach high normalized ion temperature gradients required in a compact fusion reactor. The comparison shows that core heat transport in neoclassically optimized stellarators is driven by the same mechanisms as in tokamaks. The absence of a strong H-mode temperature edge pedestal in stellarators, sofar (which, like in tokamaks, could lift the clamped temperature-gradients in the core), puts a strong requirement on reliable and sustainable core turbulence suppression techniques in stellarators.

Published
2021

41. Inhibition of parametric decay in heating microwave beams during fluctuations of the density profile in the edge island of Wendelstein 7-X

Author

W7-X Team, Tancetti, A., Nielsen, S. K., Rasmussen, J., Moseev, D., Stange, T., Marsen, S., Vecséi, M., Killer, C., Wurden, G. A., Jensen, T., Stejner, M., Anda, G., Dunai, D., Zoletnik, S., Rahbarnia, K., Brandt, C., Thomsen, H., Hirsch, M., Hoefel, U., Chaudhary, N., Winters, V., Kornejew, P., Harris, J., Laqua, H. P., Gantenbein, Gerd, Illy, Stefan, Jelonnek, John, Krier, Laurent, and Thumm, Manfred

Subjects
Technology, Nuclear Energy and Engineering, Condensed Matter Physics, ddc:600
Abstract

Experimental evidence of parametric decay instability (PDI) is observed in the Wendelstein 7-X stellarator, when high-power microwave beams cross a stationary magnetic island at the plasma edge. Here, trapping and build-up of upper hybrid waves within a density bump (measured within the island by alkali beam emission spectroscopy) is responsible for the reduction of the instability power threshold below the maximum gyrotron power. In this paper, we provide the first experimental evidence of the connection between the trapping mechanism in the island density bump and excitation of PDI-related signals. We show correlations of periodic crashes in the PDI-related signals with quasi-continuous fluctuations at the plasma edge, which, additionally, cause a flattening of the density profile in the island. We demonstrate that flattening of the experimental density profiles can suppress the trapping mechanism and inhibit the low-threshold PDI. PDI on the edge island could alter the power deposition profile and reduce the efficiency of the electron cyclotron resonance heating system, simultaneously posing a serious threat to the optimal operation of microwave-based diagnostics and plasma-facing components.

Published
2022

44. Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

W7-X Team, Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., Höfel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., Äkäslompolo, S., Alcusón, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., Bähner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Böckenhoff, D., Böswirth, B., Böttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttenschön, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Molin, A. da, Silva, A. da, Pena, A. de la, Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Köchl, F., Kolesnichenko, Y., Könies, A., König, R., Kornejew, P., Koschinsky, J.-P., Köster, F., Krämer, M., Krampitz, R., Krämer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lücke, A., Lumsdaine, A., Lutsenko, V., Maaßberg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morisaki, T., Moseev, D., Murakami, S., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ölmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuß, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Pölöskei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., Röhlinger, H., Romé, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schlüter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szabó, V., Szabolics, T., Szepesi, T., Szökefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipán, S., Unterberg, B., Vakulchyk, I., Valet, S., Vanó, L., Eeten, P. van, Milligen, B. van, Vuuren, A. J. van, Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Stechow, A. von, Vorköper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Applied Physics and Science Education, Science and Technology of Nuclear Fusion, Turbulence in Fusion Plasmas, and European Commission

Subjects
Magnetically Confined Plasmas, Tokamak, Design, Helias, Nuclear engineering, Magnetically confined plasmas, 01 natural sciences, 7. Clean energy, Article, Plasma physics, 010305 fluids & plasmas, law.invention, law, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, 010306 general physics, Engineering & allied operations, Stellarator, Physics, Plasma fusion, Multidisciplinary, Toroid, biology, Plasma Physics, Física, Magnetic confinement fusion, Plasma, biology.organism_classification, Energía Nuclear, ddc:620, Wendelstein 7-X
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., Previously documented record values of the fusion triple product in the stellarator Wendelstein 7-X are shown to be evidence for reduced neoclassical energy transport in this optimized device.

Published
2021

45. Publisher Correction: Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., H��fel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., ��k��slompolo, S., Alcus��n, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., B��hner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., B��ckenhoff, D., B��swirth, B., B��ttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Br��uer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttensch��n, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., De La Pena, A., Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., Garc��a Rega��a, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., H��lting, A., H��schen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., K��chl, F., Kolesnichenko, Y., K��nies, A., K��nig, R., Kornejew, P., Koschinsky, J.-P., K��ster, F., Kr��mer, M., Krampitz, R., Kr��mer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., K��hner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., L��cke, A., Lumsdaine, A., Lutsenko, V., Maa��berg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., M��nnich, T., Morisaki, T., Moseev, D., Murakami, S., N��fr��di, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., N��hrenberg, C., N��hrenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., ��lmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfu��, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., P��l��skei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., R��csei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., R��hlinger, H., Rom��, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., S��nchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schl��ter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schr��der, M., Schr��der, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipli��, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szab��, V., Szabolics, T., Szepesi, T., Sz��kefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulip��n, S., Unterberg, B., Vakulchyk, I., Valet, S., Van��, L., Van Eeten, P., Van Milligen, B., Van Vuuren, A. J., Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Von Stechow, A., Vork��per, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., and Zuin, M.

Subjects
Chemical engineering, ddc:660
Published
2021

46. Confinement degradation and plasma loss induced by strong sawtooth crashes at W7-X

Author

W7-X Team, Zanini, M., Buttenschön, B., Laqua, H. P., Thomsen, H., Stange, T., Brandt, C., Braune, H., Brunner, K. J., Dinklage, A., Gao, Y., Hirsch, M., Höfel, U., Knauer, J., Marsen, S., Marushchenko, N., Pavone, A., Rahbarnia, K., Schilling, J., Turkin, Y., Wolf, R. C., Zocco, A., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Scherer, Theo, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Technology, Nuclear and High Energy Physics, Materials science, Plasma, Sawtooth wave, Condensed Matter Physics, 01 natural sciences, Molecular physics, 010305 fluids & plasmas, 0103 physical sciences, ddc:530, 010306 general physics, ddc:600, Degradation (telecommunications)
Abstract

Sawtooth-like crashes were observed during electron cyclotron current drive experiments for strikeline controls at the optimised superconducting stellarator Wendelstein 7-X (W7-X). The majority of the crashes did not have a relevant impact on plasma performance. However, a limited number of events, characterised by a large plasma volume affected by the instability, have been related to a strong deterioration performance and even to the premature termination of the plasma. The hot plasma core expelled during these sawtooth crashes can reach the plasma edge, where plasma surface interaction can occur and impurities can be released. The x-ray tomography shows a strong radiation increase starting from the edge and moving towards the inner plasma regions. This results in the cooling down and shrinking of the plasma, which eventually leads to a poor coupling of the ECRH to the electrons, that can in turn result in a plasma loss. A relation between the size and amplitude of the sawtooth crashes and the impurity increase is reported.

Published
2021

50. Validation of theory-based models for the control of plasma currents in W7-X divertor plasmas

Author

Dinklage, A., primary, Fuchert, G., additional, Wolf, R.C., additional, Alonso, A., additional, Andreeva, T., additional, Beidler, C.D., additional, de Baar, M., additional, Gao, Y., additional, Geiger, J., additional, Jakubowski, M., additional, Laqua, H., additional, Marushchenko, N., additional, Neuner, U., additional, Pablant, N., additional, Pavone, A., additional, Rahbarnia, K., additional, Schmitt, J., additional, Smith, H.M., additional, Stange, T., additional, and Turkin, Yu., additional

Published
2021
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