Positive corona streamer interaction with metalized dielectric: Possible mechanism of cathode destruction

Abstract

This paper examines the effect of pulsed positive point-to-plane corona discharge in millimeter air gaps on the surface of a metalized dielectric. A footprint method was applied to reveal the streamer–surface interaction with Al and Zn thin films (20–50 nm) as a sensitive indicator. A thin metal film-dielectric substrate system was destructed at relatively low typical average currents of 20–50 μA during exposure times of 2–200 s. Destruction occurred in local zones with a size of several μm2 per one discharge pulse, which is substantially lower than the conventional streamer size of several tens of micrometers. An offered model of electro-thermal heating of the cathode layer shows that the dielectric surface temperature can achieve 1000 K and more during the single current pulse of submicrosecond duration. The indicated mechanism is possibly responsible for the effects of the discharge plasma interaction with low heat conductivity cathodes, including biological objects. Intensive heating of the cathode layer should be considered when modeling the streamer–cathode interaction.