An investigation of a dc dielectric barrier discharge using a disc ofglass beads

Abstract

We discuss the properties of a dc discharge which occurs atthe interfaces between a disc of fused glass beads and parallel electrodes.The discharge consisted of a large number of microdischarges. The dischargecurrent had a large number of pulses superimposed on a dc backgroundcurrent. The background current increased with decreasing bead size anddecreased as the separation between the disc and the electrode increased.The current had an extremely slow and nonlinear transient behaviour when thedc high-voltage source was switched on. The frequency of the current pulsesdecreased with increasing bead size and disc-electrode separation. Theaverage amplitude of the pulses, in contrast, increased with increasing beadsize and disc-electrode separation. A significant dependence of theproperties of the current pulses on the polarity of the applied voltage wasobserved, although the dc current was almost independent of the polarity. Itwas found that the enhancement of the electric field near the contact pointsbetween the electrode and the beads, where the current concentrates,initiates the discharge. The density of ozone produced by the discharge wasalso measured. Damage to the discs by the discharge was also observed,thereby altering the properties of the discharge.