The properties of triggered vacuum gaps

The reaction of the trigger plasma of triggered vacuum gaps (TVGs) to the main gap voltage changes with the main gap polarity. The trigger polarity has no influence when the main gap voltage exceeds a certain value. The high current-chopping instability in positive TVG mode is investigated in detail, with the influence of the loop parameters and electrode contamination. In the negative mode, a history effect is found in TVG triggering, associated with the surface condition of the main gap cathode. The trigger delay time in the negative mode depends on the trigger plasma density and the plasma buildup. The general TVG triggering is explained, and the reaction of the trigger plasma to the main gap polarity determines the main-gap polarity dependence of TVG. >