MECHANISM OF ELECTRICAL BREAKDOWN LEFT OF PASCHEN MINIMUM

The breakdown mechanism of a gas at small PD values is considered. Com paring experimental results and theoretical analysis, the limits of di fferent breakdown mechanisms are established. For SF6 and Ar gases the conditions for streamer and those for the Townsend breakdown mechanis m are found, as well as those for vacuum breakdown. The pressure value s characteristic for avalanche and emission mechanisms of vacuum break down are obtained. Left from the Paschen minimum in the vicinity of th e minimum point, edge-type breakdown is dominating, which currently is misinterpreted as an anomalous Paschen effect.