Investigation on the electrode surface roughness effects on a repetitive self-breakdown gas switch

In this work, the influence of the electrode surface roughness on the self-breakdown gas switch is investigated by physical analysis, computer simulation and experiment. Cu-W electrodes of different surface roughness were tested under the conditions of a pulse repetitive frequency of 50 Hz, self-breakdown voltage of ～30 kV, and peak current of ～2 kA for ～93000 shots (the total charge transferred was ～15 C). The coefficients of variation of the self-breakdown voltage of Cu-W 0.8, Cu-W 3.2 and Cu-W 12.5 electrodes were ～2.95%, ～1.62% and ～1.16%, respectively. With the increase of electrode roughness, the erosion area decreased continuously, indicating that the breakdown positions were more stable and the coefficient of variation of breakdown voltage decreased. The method showed that decreasing the coefficient of variation of the self-breakdown voltage by increasing the surface roughness of electrode greatly improves the stability of the self-breakdown switch, which is significant for their application in compact high-power pulse power devices over a long time with stable operation.