Partial electrostatic discharge induced by precharged dielectric surfaces

When a blunt-nosed earthed object approaches a dielectric surface bearing strong levels of precharging, a micro-spark ensues within sub-mm distance. When the same object is sharp-nosed, on the other hand, a different mode has been found to apply: in place of sparking, tip corona leading to slow surface-wide neutralization would begin at a separation on the order of multiple cms. This work studies the phenomenon in selective experiments using dielectric surfaces precharged by both polarities with corona onset triggered at finite potentials. Current waveforms indicate inverse RF pulsing, which shares some common features with the familiar Trichel pulsing. Also noted is the phenomenon of pulse-bunching near onset condition of inverse corona, in which groups of such pulses, typically a few in each, would occur in quick but irregular succession.