Mechanism of the pseudospark initiation for the switches with a trigger unit based on flashover

One of the methods for triggering a pseudospark switch implies a use of a surface discharge (flashover) in a trigger unit, which is normally placed inside the main cathode cavity. In various designs of the switches the surface discharge is ignited over a dielectric insert with low ε, a dielectric insert with high ε, a semiconductor insert and so on. The present paper demonstrates that the best results on triggering are achieved when, during the flashover development, a potential difference appears between the flashover plasma and the main cathode cavity. Mechanism for the main discharge initiation is general for most of the trigger systems. It is associated with the current interception from the trigger plasma to the main cathode cavity and the succeeding development of discharge in the main gap. The features of development of the main discharge at the initial stages of formation and burning are also discussed.