Artículo
An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor
Autor/es | Bernert, M.
Brezinsek, S. Carr, M. Henderson, S.S. Cavedon, M. Jet Contributors García Muñoz, Manuel |
Departamento | Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear |
Fecha de publicación | 2019-01 |
Fecha de depósito | 2020-07-08 |
Publicado en |
|
Resumen | 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 ... 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, P-sep, 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 approximate to 2% to approximate to 9% as P-sep, is increased from approximate to 2.5 MW to approximate 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. |
Identificador del proyecto | 633053
EP/P012450/1 |
Cita | Bernert, M., Brezinsek, S., Carr, M., Henderson, S.S., Cavedon, M., Jet Contributors, y García Muñoz, M. (2019). An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor. Nuclear Materials and Energy, 18, 147-152. |
Ficheros | Tamaño | Formato | Ver | Descripción |
---|---|---|---|---|
1-s2.0-S2352179118301601-main.pdf | 2.156Mb | [PDF] | Ver/ | |