Lithium Surface Coatings for Improved Plasma Performance in NSTX

[摘要] NSTX high-power divertor plasma experiments have shown, for the first time, significant and frequent benefits from lithium coatings applied to plasma facing components. Lithium pellet injection on NSTX introduced lithium pellets with masses 1 to 5 mg via He discharges. Lithium coatings have also been applied with an oven that directed a collimated stream of lithium vapor toward the graphite tiles of the lower center stack and divertor. Lithium depositions from a few mg to 1 g have been applied between discharges. Benefits from the lithium coating were sometimes, but not always seen. These improvements sometimes included decreases plasma density, inductive flux consumption, and ELM frequency, and increases in electron temperature, ion temperature, energy confinement and periods of MHD quiescence. In addition, reductions in lower divertor D, C, and O luminosity were measured.

[发布日期] 2008-02-19

[学科分类] 原子、分子光学和等离子物理

[关键词] COATINGS;CONFINEMENT;DIVERTORS;ELECTRON TEMPERATURE;GRAPHITE;ION TEMPERATURE;LITHIUM;LUMINOSITY;OVENS;PELLET INJECTION;PELLETS;PERFORMANCE;PLASMA;PLASMA DENSITY;SURFACE COATING NSTX