Observation of non-thermal electrons outside the SOL in the Wendelstein 7-X stellarator

C. Killer; P. Aleynikov; C. Biedermann; C.P. Dhard; P. Drews; Y. Gao; O. Grulke; M. Jakubowski; A. Knieps; G. Kocsis; D. Naujoks; A. Puig Sitjes; M. Spolaore; T. Stange; T. Szepesi; A. Tancetti; H. Thomsen

Nuclear Materials and Energy (Oct 2022)

Observation of non-thermal electrons outside the SOL in the Wendelstein 7-X stellarator

C. Killer,
P. Aleynikov,
C. Biedermann,
C.P. Dhard,
P. Drews,
Y. Gao,
O. Grulke,
M. Jakubowski,
A. Knieps,
G. Kocsis,
D. Naujoks,
A. Puig Sitjes,
M. Spolaore,
T. Stange,
T. Szepesi,
A. Tancetti,
H. Thomsen

Affiliations

C. Killer: Max-Planck Institute for Plasma Physics, Greifswald, Germany
P. Aleynikov: Max-Planck Institute for Plasma Physics, Greifswald, Germany
C. Biedermann: Max-Planck Institute for Plasma Physics, Greifswald, Germany
C.P. Dhard: Max-Planck Institute for Plasma Physics, Greifswald, Germany
P. Drews: Forschungszentrum Jülich, Germany
Y. Gao: Max-Planck Institute for Plasma Physics, Greifswald, Germany
O. Grulke: Max-Planck Institute for Plasma Physics, Greifswald, Germany; Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
M. Jakubowski: Max-Planck Institute for Plasma Physics, Greifswald, Germany
A. Knieps: Forschungszentrum Jülich, Germany
G. Kocsis: Center for Energy Research, Budapest, Hungary
D. Naujoks: Max-Planck Institute for Plasma Physics, Greifswald, Germany
A. Puig Sitjes: Max-Planck Institute for Plasma Physics, Greifswald, Germany
M. Spolaore: Consorzio RFX, Padova, Italy; Institute for Plasma Science and Technology (ISTP), CNR, Italy
T. Stange: Max-Planck Institute for Plasma Physics, Greifswald, Germany
T. Szepesi: Center for Energy Research, Budapest, Hungary
A. Tancetti: Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
H. Thomsen: Max-Planck Institute for Plasma Physics, Greifswald, Germany

Journal volume & issue: Vol. 33
p. 101274

Abstract

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Hot spots and bright patterns on plasma-facing components (PFC) in visible light are observed in electron cyclotron resonance heated (ECRH) plasmas at low densities in the stellarator Wendelstein 7-X. The events are often located far outside of any convective plasma loads and led in some cases to damages of diagnostic components, where the interaction zones qualitatively agree with fast particle loss simulations. Reciprocating electric probes indicate that this phenomenon is related to a non-thermal electron population that can have a beam like character, being directed in one parallel direction. Further, the electrons can be trapped on rational flux surfaces and be used to map magnetic islands.

Published in Nuclear Materials and Energy

ISSN: 2352-1791 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: http://www.journals.elsevier.com/nuclear-materials-and-energy/

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