Discharge formation processes and glow-to-arc transition in pseudospark switch

This paper deals with an interpretation of the current sustaining mechanisms at different stages of the high-current low pressure pulsed gas discharge with hollow cathode (pseudospark discharge). The analysis of experimental data for the stage of delay time to breakdown and the subsequent stages is presented. The principal features of glow stages are interpreted in the framework of the concept of nonmonotonic potential distribution in the near cathode regions. It is shown that in spite of extremely high current density the main fraction of the discharge current at the cathode surface is carried by ion component. In the superdense glow stage the ion current is provided due to numerous microexplosions of the cathode surface, ionization of the metal vapor inside the cathode voltage drop region, and returning the metal vapor back to the cathode in a form of ions. The glow mode in this case is determined by a uniform distribution of the explosion centers over the cathode.