Spatio-temporal dynamics of discharge domains in a dielectric barrier discharge device

The spatio-temporal correlation of discharge filaments in dielectric barrier discharges in air at atmospheric pressure is studied using an optical method. The stable filament patterns are achieved by using water electrodes, which serve both as coolants and transparent media for observation. It is found that the time interval between the two discharges of a filament in two consecutive half-cycles alternates between the long one and the short one, in general. An equation describing breakdown/termination of discharges is suggested by considering the effect of accumulated charges on the dielectric surface, and the experimental phenomena mentioned above can be explained using this equation. It is found in our experiments that the mapping of the delay time sequence for a filament has metastability with certain fluctuation features. The stable filament pattern can be divided into discharge domains. Each domain consists of several neighbouring filaments. The discharges of the filaments inside a domain are cooperatively correlated, while those of neighbouring domains are most likely competitively correlated.