Spatial and temporal distribution of potential in the pseudospark switch

The understanding of emission and transport in the pseudospark is complex because these are related to a transition between two fundamentally different modes of electron emission. In this paper probe measurements of plasma parameters are presented providing evidence for oscillatory behavior of the current and potential during this transition. It is shown that these fluctuations are related to a glow-to-arc transition wherein smooth current growth is interrupted by cathode spot formation inside of the hollow cathode resulting in very rapid rise in current. These results support a view that quenching observed in the pseudospark is a double-layer phenomenon that occurs when emission cannot exceed secondary emission produced by ion bombardment.<
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