Instabilities and Plasma Flares in Moderate-Current Confined Magnetron Sputtering in Three Dimensions

Abstract

Plasma instabilities, spokes, and flares are important in low-temperature cross-field devices (think magnetron sputtering, or Hall thrusters for spacecraft), yet their roles in discharge maintenance and charged-particle transport are not fully understood. The authors use high-speed photography to investigate the formation of plasma flares, and low-frequency oscillations in the plasma potential. At high power there is a drastic change in plasma characteristics, and the oscillations become chaotic. The instabilities assist particle transport far from the cathode, which may be of considerable technological importance.