This title appears in the Scientific Report :
2021
Please use the identifier:
http://dx.doi.org/10.1088/1402-4896/ab753f in citations.
Please use the identifier: http://hdl.handle.net/2128/27484 in citations.
Long pulse D 2 and N 2 seeded discharges on the upper actively cooled tungsten divertor of WEST
Long pulse D 2 and N 2 seeded discharges on the upper actively cooled tungsten divertor of WEST
A series of L-mode discharges in upper single null configuration with more than 30 s duration were performed in the WEST tokamak with the strike line on actively cooled tungsten-coated divertor components. This series of discharges accumulated 20 min of plasma and a strike point fluence of $\approx...
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Personal Name(s): | Dittmar, T. (Corresponding author) |
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Loarer, T. / Drenik, A. / Bourdelle, C. / Brezinsek, S. / Desgranges, C. / Douai, D. / Fedorczak, N. / Guirlet, R. / Gunn, J. / Meyer, O. / Laguardia, L. / Tsitrone, E. | |
Contributing Institute: |
Plasmaphysik; IEK-4 |
Published in: | Physica scripta, T171 (2020) S. 014074 - |
Imprint: |
Stockholm
The Royal Swedish Academy of Sciences
2020
|
DOI: |
10.1088/1402-4896/ab753f |
Document Type: |
Journal Article |
Research Program: |
Plasma-Wall-Interaction |
Link: |
Get full text Published on 2020-06-24. Available in OpenAccess from 2021-06-24. |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/27484 in citations.
A series of L-mode discharges in upper single null configuration with more than 30 s duration were performed in the WEST tokamak with the strike line on actively cooled tungsten-coated divertor components. This series of discharges accumulated 20 min of plasma and a strike point fluence of $\approx 2\times {10}^{25}\,{{\rm{m}}}^{-2}$ in two days of operation in attached conditions. The discharges showed good density control, no tungsten accumulation and overall very benign thermal behaviour of the upper divertor. A subset of the discharges were seeded with nitrogen either in the divertor or midplane region to study plasma–wall interaction and associated ammonia formation in this weakly pumped scenario with all-tungsten plasma-facing components. While ammonia signals remained too weak for useful analysis, a strong dependence of nitrogen plasma penetration efficiency and residence time on the injection location was found. This hints towards a currently underestimated plasma-near nitrogen reservoir in these tokamak discharges in divertor configuration. |