Glow-spark switching by a dielectric wall in a pin-to-electrolyte discharge

In this paper, the shape, sound, and current of an electrical discharge in the air between a metal pin and an electrolyte solution are studied. Two different situations are considered: (A) without, and, (B) with inclusion of a dielectric wall in the discharge circuit. It is found that: (1) the discharge A has a cylindrical shape rather than a branched shape in discharge B, (2) the sound and current of discharge in case A are coherent and deterministic but those of case B are incoherent and stochastic. These differences along with the simulation results of a simple model demonstrate that the discharge in case A is glow, but, that in case B is spark.