Breakdown Characteristics of Nitrogen under Unipolar Applied Voltages for Non-Uniform Field Configuration

This paper presents work on breakdown studies conducted in nitrogen at partial vacuum conditions for a point-to-plane electrode setup. The experiments are conducted under two different applied fields of 20 kHz unipolar pulsed square wave and 20 kHz unipolar sinusoid (DC shifted sinusoid). The applied square pulsed signal consists of a train of pulses at 20 kHz with 50% duty cycle and rise/fall times around 20 ns as well as the sinusoidal signal. The gas pressure is varied from 0.1 to 4.0 torr to observe breakdown voltage variation as a function of pressure and a Paschen like behavior is observed. Preliminary data of voltage and current waveforms, along with the light emission data collected by a PMT (photo multiplier tube) as a function of the time are presented. Also, the spectrum of the discharge listing the active transitions is presented.