Preliminary tests of megavolt inverse-pinch plasma switch

Preliminary tests of the megavolt inverse pinch plasma switch (INPIS) were successfully completed. The tested voltage ranged from 50 to 250 kV. The hold-off voltage was determined as a function of N₂ pressure, and the results showed that the multigap INPIS had higher hold-off voltage at a given pressure-distance product than single-gap switches. Over-volt breakdown of the INPIS gap was found to be very uniform azimuthally even without an external trigger. Therefore, the current commutation in the INPIS had a fast risetime (approximately 10 ns). The recovery time of the INPIS is sufficiently fast for 10 Hz operation. Furthermore, having a uniform current flow in the annular gap is advantageous for high Coulomb transfer required by a high-power compact pulser. The extrapolation of the tested results indicates that the INPIS, with the N₂ pressure of 2.76 atm, may be able to meet the requirements for a 36 kJ compact pulser