Different performance of UV laser induced surface flashover

The flashover phenomenon for the unilluminated case along the interface of solid dielectric in vacuum is the main factor which restricts the performance of high pulsed power devices, and there are plenty of investigations devoted into determining which parameters are important in predicting flashover behavior and the theoretical understanding involved in the process in the past several decades. In this paper, we studied the flashover performance in the UV laser illuminated case. A testbed comprised of a pulsed high voltage power supply, a vacuum chamber, and an excimer laser was assembled to test the flashover behavior under pulsed voltage and UV laser irradiation. Finger electrode was used in our experiments for this kind of electrode is convenient to observe flashover events. A commercial energy meter was used to measure the UV fluence for each laser pulse. The flashover voltage and flashover current were measured for different illuminated positions to determine the flashover time delay. At last, an interpretation was made to explain these experiment results. In conclusion, the UV laser irradiation induced surface flashover has different phenomena compared to the unilluminated case. These results will provide new guidelines to improve the surface flashover voltage when designing pulsed power systems.