WHISTLER MODE ELECTRON CYCLOTRON RESONANCE HEATING AND EMISSION IN A MAGNETIC MIRROR PLASMA. (VOLUMES I AND II).

摘要

An experimental investigation has been conducted in which whistler mode electron cyclotron heating (ECRH) was performed simultaneously with whistler mode electron cyclotron emission measurements on an axisymmetric magnetic mirror plasma. Results presented include theoretical and experimental studies of the early plasma startup phase, as well as experimental studies of two instability phases. These instabilities are identified as a whistler instability and a magnetohydrodynamics (MHD) flute instability.;Experimentally measured heating rates show good agreement with a numerical simulation code based on rate equations and simplified analytical models of stochastic ECRH. Experimentally observed sensitivity of plasma startup to neutral and gas pressure is also consistent with the rate equation computer model. Improved hot electron trapping is experimentally identified with moving the ECH resonance closer to the mirror midplane.;Enhanced microwave emission at frequencies below the midplane electron cyclotron frequency has been correlated with enhanced electron endloss and radially outward hot electron motion during the whistler instability. Onset of this instability appears consistent with theoretically derived density thresholds for absolute instability. In addition, the experimental evidence suggests a possible instability coupling in which the flute instability is triggered by the whistler instability.;Finally, contributions have been made to the development of magnetic fusion energy technology. This includes contributions to the areas of microwave launching antennas, plasma fueling techniques suitable for whistler mode ECRH startup, high power microwave voltage source switching, and further development of diagnostics most suitable for monitoring ECRH plasma conditions.;Cyclotron emission spectra during the startup phase match that predicted for a "sloshing electron" type distribution based on radiation transport numerical modelling. This sloshing electron distribution has been confirmed by independent Langmuir probe measurements. It is also in good agreement with anisotropic distributions resulting from ECRH as predicted by Fokker-Planck computer simulations.