A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Toroidal asymmetries in divertor impurity influxes in NSTX
Toroidal asymmetries in divertor carbon and lithium influxes were observed in NSTX, due to toroidal differences in surface composition, tile leading edges, externally-applied three-dimensional (3D) fields and toroidally-localized edge plasma modifications due to radio frequency heating. Understanding toroidal asymmetries in impurity influxes is critical for the evaluation of total impurity sources, often inferred from measurements with a limited toroidal coverage. The toroidally-asymmetric lithium deposition induced asymmetries in divertor lithium influxes. Enhanced impurity influxes at the leading edge of divertor tiles were the main cause of carbon toroidal asymmetries and were enhanced during edge localized modes. Externally-applied 3D fields led to strike point splitting and helical lobes observed in divertor impurity emission, but marginal changes to the toroidally-averaged impurity influxes. Power coupled to the scrape-off layer SOL plasma during radio frequency (RF) heating of H-mode discharges enhanced impurity influxes along the non-axisymmetric divertor footprint of flux tubes connecting to plasma in front of the RF antenna. Keywords: NSTX, Divertor, Impurities, Sputtering, Toroidal asymmetry,
Toroidal asymmetries in divertor impurity influxes in NSTX
Toroidal asymmetries in divertor carbon and lithium influxes were observed in NSTX, due to toroidal differences in surface composition, tile leading edges, externally-applied three-dimensional (3D) fields and toroidally-localized edge plasma modifications due to radio frequency heating. Understanding toroidal asymmetries in impurity influxes is critical for the evaluation of total impurity sources, often inferred from measurements with a limited toroidal coverage. The toroidally-asymmetric lithium deposition induced asymmetries in divertor lithium influxes. Enhanced impurity influxes at the leading edge of divertor tiles were the main cause of carbon toroidal asymmetries and were enhanced during edge localized modes. Externally-applied 3D fields led to strike point splitting and helical lobes observed in divertor impurity emission, but marginal changes to the toroidally-averaged impurity influxes. Power coupled to the scrape-off layer SOL plasma during radio frequency (RF) heating of H-mode discharges enhanced impurity influxes along the non-axisymmetric divertor footprint of flux tubes connecting to plasma in front of the RF antenna. Keywords: NSTX, Divertor, Impurities, Sputtering, Toroidal asymmetry,
Toroidal asymmetries in divertor impurity influxes in NSTX
F. Scotti (author) / V.A. Soukhanovskii (author) / J.-W. Ahn (author) / A.G. McLean (author) / R. Kaita (author)
2017
Article (Journal)
Electronic Resource
Unknown
Metadata by DOAJ is licensed under CC BY-SA 1.0
Optimization of the snowflake divertor for power and particle exhaust on NSTX–U
| DOAJ | 2019
Predictive modeling of a lithium vapor box divertor in NSTX-U using SOLPS-ITER
| DOAJ | 2021
Heat influxes and flame heights on external facades from enclosure fires
| UB Braunschweig | 2006