MODE JUMPS AND HYSTERESIS IN SURFACE-WAVE SUSTAINED MICROWAVE DISCHARGES

Various electromagnetic surface modes along a finite area dielectric i nterface can sustain large area overdense plasmas. Mode jumps between these modes have been reported when changing the gas pressure. In this paper we report similar mode jumps caused by changing the wave power at fixed gas pressure. A simple theoretical analysis is proposed to ex plain this phenomenon on the basis of the resonance behavior of the ch amber impedance and a stability criterion is formulated. The theory pr edicts a hysteresis in the power-density dependence, which was also ob served experimentally.