High Average Power Hydrogen Spark-gap Experiments

High-pressure gas switches enjoy widespread use in the scientific and commercial communities because of their ability to operate over a wide range of voltages and currents. However, a simultaneous requirement of continuous operation at high average power and high repetition rate has quite often limited their use. Improvement in the rep-rate capability of high pressure gas switches has been extensively investigated at the Dahlgren Laboratory of the Naval Surface Warfare Center (NSWC). Past work has demonstrated burstmode pulse repetition frequencies to 10 kHz, at voltages up to 500 kV or currents to 170 kA, by operating various highpressure hydrogen switches at approximately 50% of their self-break voltages. This paper describes recent work demonstrating continuous operation of one of these switches. Repetition rates up to 1.7 kHz at an average power of 16.5 kW and an operating voltage of 40 kV for >70 seconds are presented. The results for repetition rates from 670 Hz to 1.7 kHz show that the recovery curve obtained for burst-mode operation is reasonably predictive for continuous operation. Variation in the breakdown voltage during continuous operation is shown to be < 3 percent. The operating voltage, frequency and average power were limited by the experimental apparatus.