Ion heating at the cyclotron resonance in plasmas magnetically confined in a toroidal octupole field

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1976

OSTI ID:7256107

Barter, J D

Ion temperatures as high as 600 eV have been produced using rf wave heating at the ion cyclotron resonance frequency in a toroidal octupole magnetic field. Rf is coupled to the plasma with an externally driven ''fifth'' hoop which forms the inductive leg of an oscillator tank circuit. Power levels up to 1 MW at 1 to 3 MHz have been applied for periods up to 2 msec. Plasmas produced either by ECRH or by gun injection are simulated with a computer program in which known particle and energy production and loss mechanisms are used to predict the spatially averaged time behaviour of the plasma in the presence of the applied ion heating. The program can be used to calculate the consequences of the heating model in the presence of many cooling mechanisms which may each have a separate dependence on instantaneous plasma parameters. Experimental quantities compared to computer predictions include density, ion temperature, and loading of the hoop by the plasma, both resistive and reactive, and neutral reflux from the wall by electron and ion impact. Wave penetration to the resonance zone is good up to the highest densities available (6 x 10/sup 12/ cm/sup -3/ by gun injection) in good agreement with theory. Neutral reflux from the walls and the large charge exchange cooling which results is the dominant loss mechanism at the higher hoop voltages.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 7256107
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
BOUNDARY LAYERS
CHARGE EXCHANGE
CLOSED CONFIGURATIONS
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
ION TEMPERATURE
LAYERS
MAGNETIC FIELD CONFIGURATIONS
MULTIPOLAR CONFIGURATIONS
OCTUPOLAR CONFIGURATIONS
PLASMA DENSITY
PLASMA HEATING