Computational modeling of spark gap density recovery after breakdown

Spark gap switch is the key element in any pulsed power system, which directly determines the pulse repetitive frequency of the system. In this study, a two-dimensional axisymmetric computational model of spark gap recovery in argon gas is presented to provide a better understanding of the dynamics of the recovery process. The estimation of the recovery time is an important issue for the repetitive pulse power systems. In this work, we investigate the decay of temperature, pressure and density of the spark channel using some assumptions. It was shown that the gas density in a 2mm spark gap filled with argon gas almost recovers around 58ms, but the hold-off voltage of the spark gap after breakdown recovers about 40% of its original over-volted breakdown voltage. The mechanism for the delayed recovery of breakdown voltage compared to gas density was discussed. The effect gas pressure on the decay time is also presented.