Characteristics of breakdown voltage at a narrow gap in a non-thermal plasma flow

Characteristics of breakdown voltage in a non-thermal plasma flow at atmospheric pressure were investigated experimentally. Breakdown voltages for different gap lengths of parallel plate electrodes were measured with respect to applied voltage rising rate, applied waveform, applied wave frequency, gas flow rate and kind of gas. The correlation between pd, which is the product of the pressure and the gap length, and breakdown voltage corresponded to Penning's experimental data of the applied voltage rising rates from 0.1 kV/s to 10 kV/s. However, the correlation was not in accordance with Penning's data when rising rates were greater than 100 kV/s. The breakdown voltages showed a minimum value when gas flow rates were 2-4 Sl/min for both argon and nitrogen gases. On the other hand, the correlation between breakdown voltage and pd corresponded to the experimental data reported by Penning, Kind and Karner concerning the cases of sawtooth wave, sinusoidal wave and square wave with different wave frequencies of 100 Hz, 1 kHz and 10 kHz. Discharge current mode is classified into two modes and it was influenced by gas flow rate.