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EMC3-EIRENE simulation of first wall recycling fluxes in W7-X with relation to H-alpha measurements

Authors :
W7-X Team
Winters, V. R.
Reimold, F.
König, R.
Krychowiak, M.
Romba, T.
Biedermann, C.
Bozhenkov, S.
Drewelow, P.
Endler, M.
Feng, Y.
Frerichs, H.
Fuchert, G.
Geiger, J.
Gao, Y.
Harris, J. H.
Jakubowski, M.
Kornejew, P.
Kremeyer, T.
Niemann, H.
Pasch, E.
Puig-Sitjes, A.
Schlisio, G.
Scott, E. R.
Wurden, G. 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
W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society
Source :
Plasma Physics and Controlled Fusion, Plasma physics and controlled fusion, 63 (4), Art.-Nr. 045016
Publication Year :
2021

Abstract

In the Wendelstein 7-X stellarator, the main locations of particle sources are expected to be the carbon divertors, baffles and graphite heat shield first wall. In this paper, the heat shield is implemented in EMC3-EIRENE to understand the expected areas and magnitudes of the recycling flux to this component. It is found that in the simulation the heat shield is not a significant source of recycling neutrals. The areas of simulated recycling flux are shown to correlate well with footprints of plasma-wetting seen in post-experimental campaign in-vessel inspection photos. EMC3-EIRENE reconstruction of line-integrated H-alpha measurements at the heat shield indicate that the majority of emission does not come from local recycling neutrals. Rather, the H-alpha signals at the heat shield are dominated by ionization of neutrals which have leaked from the divertor/baffle region into the midplane. The magnitude of the H-alpha line emission from the synthetic reconstruction is consistent with the experiment, indicating that a large overestimation of heat shield recycling would occur if these measurements were assumed to be from local recycling sources. In the future, it may be possible to obtain some information of local recycling from the heat shield since it was found that the majority of the recycling flux occurs on two well-localized areas.

Details

Language :
English
ISSN :
07413335 and 13616587
Database :
OpenAIRE
Journal :
Plasma Physics and Controlled Fusion, Plasma physics and controlled fusion, 63 (4), Art.-Nr. 045016
Accession number :
edsair.doi.dedup.....2d6f899b6ab9d3f7c78883be4002fac9