Experimental investigation of formation time in single-gap pseudospark discharge

Experiment results on the formation of pseudospark discharge in single-gap device are presented. The formation process is investigated by capacitive probes and shows two phases: a slow ignition phase and a fast current increasing phase. The ignition of the discharge is found to be synchronous with a high speed ionization wave propagating from cathode to anode. Transition to the high current phase is initiated when the ionization front reaches the anode side. The experimental results on four different gap widths are presented under different pressures. The characteristic time of the ignition phase of the discharge is decreased with increasing pressure in all four gap widths. The mean velocity of the observed ionization front varies from 5.4×10 to 1.7×10 ³cms ¹ under the investigated pressures. In four gap widths, the velocity of the ionization front can be fitted by one given curve as an exponential decline function of E/P.