TY - JOUR
T1 - Electron-cyclotron-resonance heating in Wendelstein 7-X
T2 - A versatile heating and current-drive method and a tool for in-depth physics studies
AU - The Wendelstein 7-X Team
AU - Wolf, R. C.
AU - Bozhenkov, S.
AU - Dinklage, A.
AU - Fuchert, G.
AU - Kazakov, Y. O.
AU - Laqua, H. P.
AU - Marsen, S.
AU - Marushchenko, N. B.
AU - Stange, T.
AU - Zanini, M.
AU - Abramovic, I.
AU - Alonso, A.
AU - Baldzuhn, J.
AU - Beurskens, M.
AU - Beidler, C. D.
AU - Braune, H.
AU - Brunner, K. J.
AU - Chaudhary, N.
AU - Damm, H.
AU - Drewelow, P.
AU - Gantenbein, G.
AU - Gao, Yu
AU - Geiger, J.
AU - Hirsch, M.
AU - Höfel, U.
AU - Jakubowski, M.
AU - Jelonnek, J.
AU - Jensen, T.
AU - Kasparek, W.
AU - Knauer, J.
AU - Korsholm, S. B.
AU - Langenberg, A.
AU - Lechte, C.
AU - Leipold, F.
AU - Trimino Mora, H.
AU - Neuner, U.
AU - Nielsen, S. K.
AU - Moseev, D.
AU - Oosterbeek, H.
AU - Pablant, N.
AU - Pasch, E.
AU - Plaum, B.
AU - Sunn Pedersen, T.
AU - Puig Sitjes, A.
AU - Wauters, T.
AU - Durodie, F.
AU - Goriaev, A.
AU - Ongena, J.
AU - Vergote, M.
AU - Vervier, M.
N1 - Publisher Copyright:
© 2018 Max-Planck-Institut für Plasmaphysik.
PY - 2019/1
Y1 - 2019/1
N2 - For stellarators, which need no or only small amounts of current drive, electron-cyclotron-resonance heating (ECRH) is a promising heating method even for the envisaged application in a fusion power plant. Wendelstein 7-X (W7-X) is equipped with a steady-state capable ECRH system, operating at 140 GHz, which corresponds to the 2nd cyclotron harmonic of the electrons at a magnetic field of 2.5 T. Ten gyrotrons are operational and already delivered 7 MW to W7-X plasmas. Combined with pellet injection, the highest triple product (0.68 ×1020 keV m-3 s), observed up to now in stellarators, was achieved (Sunn Pedersen et al 2018 Plasma Phys. Control. Fusion 61 014035). For the first time, W7-X plasmas were sustained by 2nd harmonic O-mode heating, approaching the collisionality regime for which W7-X was optimized. Power deposition scans did not show any indication of electron temperature profile resilience. In low-density, low-power plasmas a compensation of the bootstrap current with electron-cyclotron current drive (ECCD) was demonstrated. Sufficiently strong ECCD close to the plasma centre produced periodic internal plasma-crash events, which coincide with the appearance of low order rationals of the rotational transform.
AB - For stellarators, which need no or only small amounts of current drive, electron-cyclotron-resonance heating (ECRH) is a promising heating method even for the envisaged application in a fusion power plant. Wendelstein 7-X (W7-X) is equipped with a steady-state capable ECRH system, operating at 140 GHz, which corresponds to the 2nd cyclotron harmonic of the electrons at a magnetic field of 2.5 T. Ten gyrotrons are operational and already delivered 7 MW to W7-X plasmas. Combined with pellet injection, the highest triple product (0.68 ×1020 keV m-3 s), observed up to now in stellarators, was achieved (Sunn Pedersen et al 2018 Plasma Phys. Control. Fusion 61 014035). For the first time, W7-X plasmas were sustained by 2nd harmonic O-mode heating, approaching the collisionality regime for which W7-X was optimized. Power deposition scans did not show any indication of electron temperature profile resilience. In low-density, low-power plasmas a compensation of the bootstrap current with electron-cyclotron current drive (ECCD) was demonstrated. Sufficiently strong ECCD close to the plasma centre produced periodic internal plasma-crash events, which coincide with the appearance of low order rationals of the rotational transform.
UR - http://www.scopus.com/inward/record.url?scp=85057775317&partnerID=8YFLogxK
U2 - 10.1088/1361-6587/aaeab2
DO - 10.1088/1361-6587/aaeab2
M3 - Article
AN - SCOPUS:85057775317
SN - 0741-3335
VL - 61
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 1
M1 - 014037
ER -