Generation and Diagnostics of Ambient Air Glow Discharge in Centimeter-Order Gaps

Re-pulsing glow discharges in gaps up to 2 cm were experimentally investigated in atmospheric pressure air. Discharge was ignited as a sequence of spark and glow discharge and sustained in a glow regime after ignition. It was confirmed that the discharge with defined parameters could be ignited without any adjustments after initiation of the discharge. The discharges were characterized by a high-speed camera, current and voltage measurements, and optical emission spectrometry (OES). Typical structure of the glow discharge consisting of cathode glow, dark faraday space, positive column, and anode glow was observed. Transition from subnormal to normal glow mode was confirmed by analysis of current and voltage waveforms. It was found by OES that the type of discharge strongly affects the ratio of produced reactive species. It was confirmed that with change of discharge from subnormal to normal glow regime, rotational temperature could vary across a wide range (from 1650 to 3500 K). The developed device allows glow discharge to be ignited with defined parameters, which makes the control of the gas temperature and ratio of reactive species possible by presetting the discharge parameters. Additionally, it was demonstrated that corona discharge or repeating spark discharges could also be generated using the developed device without additional manipulations of the experimental setup by adjusting the discharge parameters.