A self-activating high-voltage, high-energy crowbar

A self-closing crowbar switch has been designed and tested up to a voltage of 500 kV. The crowbar utilizes the consistent nature of electrical breakdown in water under highly non-uniform electric fields as the timing mechanism for closure and has no requirement for external triggering. The device can be operated with closure times which are controllable over the range 200-500 ns by altering the gap spacing of the switch electrodes. Measurements of the crowbar performance are presented, as well as the important aspects associated with the electrostatic design.