Advances in High-harmonic Fast Wave Physics in the National Spherical Torus Experiment

Taylor, G ; Hosea, J C ; LeBlanc, B P ; Phillips, C K ; Podesta, M ; Valeo, E J ; Wilson, J R ; Ahn, J -W ; Chen, G ; Green, D L ; Jaeger, E F ; Maingi, R ; Ryan, P M ; Wilgen, J B ; Heidbrink, W W ; Liu, D ; Bonoli, P T ; Brecht, T ; Choi, M

关键词: BEAM INJECTION;    CAMERAS;    DECAY;    DEUTERIUM;    EDGE LOCALIZED MODES;    ELECTRIC CURRENTS;    ELECTRONS;    HEATING;    LITHIUM;    NEUTRONS;    PHYSICS;    PLASMA;    ROTATION;    START-UP;    WAVELENGTHS;   

DOI  :  10.2172/969309
RP-ID  :  PPPL-4475
PID  :  OSTI ID: 969309
Others  :  TRN: US1000931

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

Improved core high-harmonic fast wave (HHFW) heating at longer wavelengths and during start-up and plasma current ramp-up, has now been obtained by lowering the edge density with lithium wall conditioning, thereby moving the critical density for perpendicular fast-wave propagation away from the vessel wall. Lithium conditioning allowed significant HHFW core electron heating of deuterium neutral beam injection (NBI) fuelled H-mode plasmas to be observed for the first time. Large edge localized modes were observed immediately after the termination of rf power. Visible and infrared camera images show that fast wave interactions can deposit considerable rf energy on the outboard divertor. HHFW-generated parametric decay instabilities were observed to heat ions in the plasma edge and may be the cause for a measured drag on edge toroidal rotation during HHFW heating. A significant enhancement in neutron rate and fast-ion profile were measured in NBI-fuelled plasmas when HHFW heating was applied. __________________________________________________