Erosion Pits Distribution Characteristics of Nanosecond Pulse Gas Spark Switches at Different Repetition Rates

Abstract

Gas spark switches are widely used in the field of nanosecond pulses. Lifetime is one of the key parameters of a gas spark switch, which is closely related to the distribution of erosion pits A repetition rate nanosecond pulsed discharge experimental platform is set up to investigate the distribution characteristics of erosion pits on the electrodes of nanosecond pulsed gas spark switch under different repetition rates. The distribution of erosion pits on the electrodes at different repetition rates has been analyzed statistically through a metallographic microscope. The results indicate that the range of erosion pits on the surface of electrodes is linearly related to the repetition rate. As the switch repetition rate increases, the range of erosion pits expands. The range of erosion pits on the cathode surface is slightly larger than that on the anode. When the repetition frequency increases from 1 Hz to 100 Hz, the radius of the anode pit range increases from 7.27 mm to 9.2 mm, and the cathode pit range increases from 8 mm to 9.73 mm. The density of erosion pits is related to the normalized electric field intensity in power function. With the increase in repetition rate, the tendency for erosion pits to concentrate at the geometric center of the electrode weakens. This research is of significant importance for the design of long-life gas spark switches.