Experimental studies of plasma heating due to the parametric decay of alarge-amplitude pump into lower-hybrid waves

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:7246921

Harper-Slaboszewicz, V J

Plasma heating of a high-density low-temperature linear plasma by the parametric decay instability of lower-hybrid waves excited in a parallel-plate geometry is studied experimentally for ww/sub lh/ = 3 and 10. The electric-field distribution is modeled considering the higher-order modes produced in this geometry. A method of measuring bulk electron temperature in the presence of an oscillating potential is developed and validated. Electron-heating results show that the parametric decay instability in this geometry is strongly driven and strongly convectively damped, resulting in very rapid electron heating that saturates in a time of 20-30w/sup -1/. Bulk electron heating consistent with a recent theory of parametric decay of a large-amplitude driver near the lower-hybrid frequency is also observed. Control of the instability by use of a finite-bandwidth driver is also studied, and results show that the threshold of the parametric decay instability in this geometry can be increased by a factor of 3 by a noise-modulated driver with ..delta..ww - .7. These results are contrasted with earlier studies.

• Research Organization: California Univ., Davis (USA)
• OSTI ID: 7246921
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700107 -- Fusion Energy-- Plasma Research-- Instabilities
COLD PLASMA
ELECTRON TEMPERATURE
HEATING
HIGH-FREQUENCY HEATING
INSTABILITY
LOWER HYBRID HEATING
MEASURING METHODS
PARAMETRIC INSTABILITIES
PLASMA
PLASMA HEATING
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES