Simulation of the discharge expansion of a spark discharge at small distances between electrodes

An important parameter for the expansion of the plasma bases at the electrodes is the expansion of plasma channel and gas bubble of the spark erosion. Simulations for the expansions on the basis of two different models are presented. The initial size of the discharge channel diameter is determined by the breakdown conditions in the narrow working gap (streamer entry). The expansion of the discharge channel parts can be simulated from the knowledge of the current and voltage curves at the gap and from the characteristics of the dielectric fluid which depends on temperature and pressure. In this context is compared a cylindrically symmetric layer model to an ellipsoidal layer model.