A diffuse argon plume generated by a longitudinal slit jet equipped with a quadri-electrode barrier discharge

A diffuse argon plume at atmospheric pressure is generated downstream of a longitudinal slit jet equipped with a dielectric barrier discharge in a quadri-electrode configuration. Results indicate that both the plume length and the spectral line intensities increase with the increase in the peak voltage. With fast photography it is found that there is a clear difference for discharges with different polarities. The positive discharge is composed of nonuniform branching filaments; however, it is fairly uniform for the negative discharge. Due to the charge overflow of the intra-electrode discharge, the streamer mechanism is involved in the plume discharge. In fact, the positive discharge and the negative one correspond to a cathode-directed streamer and an anode-directed streamer, respectively. The formation mechanisms of the branching filaments and the diffuse background are discussed at last.