PREBREAKDOWN DENSITY CHANGE STREAMER IN LIQUID-NITROGEN

The prebreakdown density change streamers and the current pulses in Li quid nitrogen were investigated A needle-plane electrode system, consi sting of a stainless steel plane and a tungsten needle whose tip radiu s is 1.01-mu m, was used throughout the experiments. The streamers und er impulse voltage conditions were observed using high-speed photograp hy for both positive and negative polarities. Two structures of stream ers, filamentary and bush-like, were found in both polarities. The mec hanisms of these streamer structures are determined by analyzing the r esults.