Numerical verification of the two-spike-current behavior in the initial stage of plasma formation in a pulsed surface dielectric barrier discharge

Abstract

Nanosecond pulsed surface dielectric barrier discharge (SDBD) is a hot topic in many fields, but the mechanisms of discharge evolution and micro-channel propagation are still not clearly understood. In this paper, a plasma fluid model of nanosecond pulsed SDBD is established, and the deductions of the two current spikes are verified and improved by simulation. The two current spikes correspond to the two stages of the discharge: the ionization wave propagation and the repeated re-ignition in the gap between the ionization wave and the dielectric surface. In the first stage, the ionization wave develops rapidly at first and propagates very slowly in the end, which produces the first current spike with a very short rise time and a tailing falling edge. The curve profile of the ionization wave velocity is very similar to that of the first current spike. A certain distance is maintained between the bottom of the ionization wave and the dielectric surface in this stage, which forms the gap for the next stage. In the second stage, the charged particle cloud induced by the quasi-uniform electric field in the middle of the gap and the new micro-channel from the edge of the high-voltage electrode propagate at first, and then merge together to establish a new discharge channel. The reverse electric field in the gap induced by the accumulated charges on the dielectric surface restricts the expansion velocity of the second discharge channel, which results in a longer rise time and falling time of the second current spike.