Transition from Glow to Arc Discharge

Abstract

I HAVE suggested¹ a mechanism to account for the occurrence of long electrical discharges in electric fields which are only of the order of one per cent of those generally believed^2,3 necessary to cause sparkover. In the case of the leader stroke of the lightning discharge, the integrated lateral corona currents from the channel ultimately reach values of the order of thousands of amperes⁴, so that the characteristics of the channel must be those of the electric arc, though the discharge must start as a brush or glow discharge. This consideration led me to suggest that the steps in the initial leader stroke represent the transition of successive lengths of the channel from glow to arc conditions, and that a self-propagating discharge is initiated by this transition.