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An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor

JET Contributors; Henderson, S. S.; Bernert, M.; Brezinsek, S.; Carr, M.; Cavedon, M.; Dux, R.; Gahle, D. S.; Harrison, J.; Kallenbach, A.; Lipschultz, B.; Lomanowski, B.; Meigs, A.; O’Mullane, M.; Reimold, F.; Reinke, M. L.; Wiesen, S.; Abduallev, S.; Abhangi, M.; ... mehr

Abstract:

The impurity concentration in the tokamak divertor plasma is a necessary input for predictive scaling of divertor detachment, however direct measurements from existing tokamaks in different divertor plasma conditions are limited. To address this, we have applied a recently developed spectroscopic N II line ratio technique for measuring the N concentration in the divertor to a range of H-mode and L-mode plasma from the ASDEX Upgrade and JET tokamaks, respectively. The results from both devices show that as the power crossing the separatrix, Psep, is increased under otherwise similar core conditions (e.g. density), a higher N concentration is required to achieve the same detachment state. For example, the N concentrations at the start of detachment increase from ≈2% to ≈9% as Psep is increased from ≈2.5 MW to ≈7 MW. These results tentatively agree with scaling law predictions (e.g. Goldston et al.) motivating a further study examining the parameters which affect the N concentration required to reach detachment. Finally, the N concentrations from spectroscopy and the ratio of D and N gas valve fluxes agree within experimental uncertainty only when the vessel surfaces are fully-loaded with N.

Zugehörige Institution(en) am KIT Institut für Angewandte Thermofluidtechnik (IATF)
Institut für Technische Physik (ITEP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 01.2019
Sprache Englisch
Identifikator ISSN: 2352-1791
KITopen-ID: 1000119910
Erschienen in Nuclear materials and energy
Verlag Elsevier
Band 18
Seiten 147-152
Bemerkung zur Veröffentlichung Kollaboration: EUROfusion MST1 Team ; ASDEX Upgrade Team
Schlagwörter Impurity, Nitrogen, Divertor, Concentration, Spectroscopy, Tokamak
Nachgewiesen in Web of Science
Scopus
Dimensions
OpenAlex
Globale Ziele für nachhaltige Entwicklung Ziel 6 – Sauberes Wasser und Sanitär-Einrichtungen

Verlagsausgabe §
DOI: 10.5445/IR/1000119910
Veröffentlicht am 29.05.2020
Originalveröffentlichung
DOI: 10.1016/j.nme.2018.12.012
Scopus
Zitationen: 8
Web of Science
Zitationen: 8
Dimensions
Zitationen: 8
Seitenaufrufe: 155
seit 02.06.2020
Downloads: 116
seit 02.06.2020
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