Characteristics of low frequency air glow dielectric barrier discharges at atmospheric pressure

In this paper we present recent studies of dielectric barriers discharges in air. The discharges are generated using an AC power supply operating at a relatively low frequency of 60 Hz between two sheets of porous dielectric material of varying thickness measuring 20 mm $\times$ 20 mm in area. Measurements are made of the optical emission and voltage--current waveforms from which we extract discharge properties including electron density, under different input voltage, electrode separation, and dielectric thickness. Stable and continuous air glow discharges were obtained at atmospheric pressure in the range of 2--5 kV and current densities of a few mA for 0.5--2.5 mm discharge gaps. Regions of stable glow discharges are mapped out and a plausible mechanism is described for the transition from glow to streamer mode. The experimental results are compared to one-dimensional numerical simulations that are carried out for a discharge pressure range of 100--760 Torr.