Statistical behavior of a single microdischarge in atmospheric-pressure air dielectric barrier discharges

Abstract

This work investigates the statistical behavior including the dimensions and electrical properties of a single microdischarge (MD) generated in a planar atmospheric-pressure air dielectric barrier discharge reactor using a kHz sinusoidal power source with a gap of 1.4 mm. The MD diameters and surface wave (SW) dimensions are captured by an intensified charge-coupled device camera with currents and charge transferred being recorded. The average currents measured in positive and negative half periods (HPs) are 58.9 and 50.5 mA, respectively. The average diameters measured are 256 and 258 μm in positive and negative HPs, respectively. Therefore, the average current densities calculated in positive and negative HPs are 1.14 × 106 and 9.66 × 105 A m−2, respectively. The high current density leads to the high density of surface charge reaching up to 51.5 nC cm−2 in the positive HP at the anode, which is one order of magnitude higher than those observed in filamentary discharges using He/N2 mixtures. The gap dimension is adjusted to 2.0 mm to investigate the effect of the gap dimension on MD properties. Larger MD diameters, currents, SW dimensions, and the charge transferred are measured in the gap of 2.0 mm although the average current densities evaluated in positive and negative HPs are lower than those of gap 1.4 mm as 9.39 × 105 and 8.15 × 105 A m−2, respectively. The average density of surface charge evaluated in the positive HP at the anode of gap 2.0 mm is 51.7 nC cm−2, which is almost identical to that evaluated in the gap of 1.4 mm.