The Effect of Pulse Width on Nanosecond Guided Streamer Breakdown

Understanding the initiation and development of guided streamers are important for effectively applying these repeatable, transient discharges for various fields. This study compares the streamer initiation and breakdown for positive helium guided streamers powered by 10-ns, 35-ns, and 200-ns voltage pulses using a hollow needle-to-plate electrode configuration at atmospheric pressure. The streamer initiation and breakdown (streamer-to-spark transition) voltage as functions of the interelectrode gap distance are determined based on voltage-current measurements and high-speed spectroscopy. The breakdown voltage for a repetitively pulsed streamer is compared with a single-shot discharge. The dependence of the pulse repetition frequency and pulse width on streamer breakdown are investigated. It is found that the shorter voltage pulses results in higher overvoltage breakdown. In addition, the discharge mode is assessed with the pulsed voltage and current as well as the rotational temperature of the 2^nd positive system of N2.