Experimental confirmation of positive-streamer-like mechanism for negative corona current pulse rise

Abstract

Current growth waveforms corresponding to initial phases of negative corona current pulses were measured in nitrogenous gas mixtures at pressures of 6.67-40 kPa. The measurements showed that the steep pulse rise is not dependent on cathode secondary emission processes for pressures above 30 kPa. This, together with a discontinuous transition in the current waveforms observed with increasing gap voltage in N2 at pressures of 20-26.6 kPa, implies that the feedback-to-cathode Townsend ionization mechanism was supplanted by a faster streamer-like mechanism. At pressures below 20 kPa a positive-streamer-like wave results in complex Trichel pulse shapes with a step on the pulse leading edge and a hump on the pulse trailing part.