Diffuse discharges of multi-needle-plane gaps sustained by repetitive nanosecond pulses at atmospheric pressure

In this paper, diffuse discharges sustained by nanosecond pulses are obtained in air gaps with a multi-needle-to-plane discharge electrode configuration at atmospheric pressure. A repetitive nanosecond generator with a rise time of 70ns and a full width at half maximum of 100ns is employed to drive diffuse discharges. Characteristics of the diffuse discharge were investigated by analyzing voltage-current waveforms and discharge images. Experimental results showed that a large-area diffuse discharge could be obtained with a pulse repetition frequency of up to 1 kHz. Furthermore, as the applied voltage increased, discharges transformed from corona discharge to diffuse mode, meanwhile the discharge current changed rapidly. It was also found that the discharge intensity varied according to the position of the needles; and discharge intensity in the center was weaker than that near the margin. In addition, the composition of the measured discharge current was calculated and analyzed.