Formation of Thermal Eddies during rf Heating of Plasma

Abstract

Moderate-power (∼1 kW) excitation of lower-hybrid waves in a linear plasma column is found to increase the reflectivity of the phased waveguide exciter and to change the vertical position of the resonance cone. Probing of the plasma near the mouth of the waveguide reveals that the increased reflection results from an undulation in the plasma surface. This Letter presents evidence that this surface distortion is driven by thermal eddies associated with asymmetrical electron heating.