Plasma decay modeling during the post-arc phase of a vacuum circuit breaker

The post-arc phase of a vacuum circuit breaker is a critical phase for dielectric recovery in the context of medium voltage current interruption. A space-charged sheath expands from the cathode to the anode and expels the residual plasma from the gap. In addition, a background density of vaporized atoms exists at the current zero. A two-dimensional hybrid model has been developed to evaluate the collisional sheath evolution during this phase in a cylindrical geometry. In this paper we show the influence on the dielectric recovery of the shield polarity with and without a given background atom density.