Effects of cathode surface properties on glow-to-arc transition in a short positive corona gap in ambient air

Measurements were made of current growth waveforms corresponding to the glow-to-arc transition in a 1 cm positive point-to-plane gap in conditions similar to those in pulsed corona devices used for flue gas cleaning. The glow-to-arc transition was significantly accelerated using a freshly polished unconditioned cathode surface. A duration of glow-to-arc transition as short as 25 ns was observed using a graphite-coated cathode. A possible explanation in terms of the cathode sheath break-ups is presented.