Powder as initial matter for pulsed high current discharges

Powder plasmas powered by a pulsed high current discharge was examined using high-speed cameras and laser imaging technique. Electrons created by a pre- ionization discharge collide with both an anode and powder particles, of which surfaces evaporate after then. Since vaporization of the anode far exceeds that of the particles, discharge characteristics is almost similar to that of vacuum sparks in which expanding anode plasmas are observed. Evaporation of the particle occurred in the hemisphere surface that is close to the cathode side. Influence of the effective anode area on the evaporation was examined by varying the anode shape to suppress the development of the anode plasma.