Mechanism of electrical breakdown left of Paschen minimum

The breakdown mechanism of a gas at small PD values is considered. Comparing experimental results and theoretical analysis, the limits of different breakdown mechanisms are established. For SF/sub 6/ and Ar gases the conditions for streamer and those for the Townsend breakdown mechanism are found, as well as those for vacuum breakdown. The pressure values characteristic for avalanche and emission mechanisms of vacuum breakdown are obtained. Left from the Paschen minimum in the vicinity of the minimum point, edge-type breakdown is dominating, which currently is misinterpreted as an anomalous Paschen effect.