Plasma radiation behavior approaching high-radiation scenarios in W7-X

Zhang, D.; Burhenn, R.; Feng, Y.; König, R.; Buttenschön, B.; Beidler, C. D.; Hacker, P.; Reimold, F.; Thomsen, H.; Laube, R.; Klinger, T.; Giannone, L.; Penzel, F.; Pavone, A.; Krychowiak, M.; Beurskens, M.; Bozhenkov, S.; Brunner, J. K.; Effenberg, F.; Fuchert, G.; Gao, Y.; Geiger, J.; Hirsch, M.; Höfel, U.; Jakubowski, M.; Knauer, J.; Kwak, S.; Laqua, H. P.; Niemann, H.; Otte, M.; Pedersen, T. Sunn; Pasch, E.; Pablant, N.; Rahbarnia, K.; Svensson, J.; Blackwell, B.; Drews, P.; Endler, M.; Rudischhauser, L.; Wang, E.; Weir, G.; Winters, V.

doi:10.1088/1741-4326/ac2b75

Plasma radiation behavior approaching high-radiation scenarios in W7-X

Journal Article · Mon Oct 25 00:00:00 EDT 2021 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ac2b75· OSTI ID:1836823

^[1]; Burhenn, R. ^[2]; ^[2]; König, R. ^[2]; ^[2]; ^[2]; Hacker, P. ^[2]; Reimold, F. ^[2]; Thomsen, H. ^[2]; Laube, R. ^[2]; Klinger, T. ^[2]; ^[3]; Penzel, F. ^[3]; ^[2]; Krychowiak, M. ^[2]; ^[2]; ^[2]; ^[2]; ^[4]; Fuchert, G. ^[2] more »

Max Planck Institute for Plasma Physics, Greifswald (Germany); OSTI
Max Planck Institute for Plasma Physics, Greifswald (Germany)
Max Planck Institute for Plasma Physics, Garching (Germany)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Australian National Univ., Canberra, ACT (Australia)
Institut für Energie und Klimaforschung - Plasmaphysik, Jülich (Germany)

The W7-X stellarator has so far performed experiments under both limiter and divertor conditions. The plasma is mostly generated by ECR-heating with powers up to 6.5 MW, and the plasma density is usually limited by the radiation losses from low-Z impurities (such as carbon and oxygen) released mainly from the graphite targets. The present work first summarizes the radiation loss fractions f_rad achieved in quasi-stationary hydrogen plasmas in both operational phases, and then shows how impurity radiation behaves differently with the two different boundary conditions as the plasma density increases. The divertor operation is emphasized and some beneficial effects (with respect to impurity radiation) are highlighted: (1) intensive radiation is located at the edge (r/a > 0.8) even at high radiation loss fractions, (2) the plasma remains stable up to f_rad approaching unity, (3) the reduction in the stored energy is about 10% for high f_rad scenarios. Moreover, effects of wall boronisation on impurity radiation profiles are also presented.

View Accepted Manuscript (DOE)

Research Organization:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of Wisconsin, Madison, WI (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Contributing Organization:: W7-X Team

Grant/Contract Number:: AC02-09CH11466; SC0014210

OSTI ID:: 1836823

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 12 Vol. 61; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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