Breakdown Development in a Pseudospark Switch with an External Trigger System Based on a Pulsed Discharge over the Surface of a Semiconductor

Abstract

A pseudospark switch with a trigger unit based on a pulsed surface discharge is investigated. The trigger system includes a semiconductor cylinder, on the surface of which there are two spring contacts. Initiation of a discharge in the high-voltage gap occurs when a trigger pulse at a level of up to 8 kV is applied to the cathode electrode. When a trigger pulse is applied, a cathode spot plasma forms in a wide range of gas (hydrogen) pressures up to atmospheric. To trigger the switch, it is necessary for the trigger discharge current to be intercepted to the grounded hollow cathode of the high-voltage gap. At low gas pressure (0.1 Torr or less), a discharge develops over the surface due to the trigger pulse, but current is not intercepted to the grounded cathode cavity. When the gas pressure increases to the working level (at a level of about 0.5 Torr), plasma is generated in the cathode cavity, which causes the external triggering of the device. The breakdown delay time relative to the instant of arrival of the trigger pulse includes the time of current interception in the cathode cavity and the time of initiation of the discharge in the main gap. It lies within the range of 55–70 ns, and its jitter for the considered trigger method does not exceed 10 ns.