Discharge dynamics of primary and secondary streamers in a repetitively pulsed surface dielectric barrier discharge

Discharge dynamics of primary and secondary streamers in a repetitively pulsed surface dielectric barrier discharge (SDBD) are investigated based on experimental and numerical simulations. Plasma propagation and coupled energy of the primary streamer are restricted in subsequent pulses, but the deposited energy of the secondary streamer increases. When the pulse repetition frequency reduces, a longer plasma length and higher average velocity of the primary streamer can be observed, but the influences on propagation length and velocity of the secondary streamer are very limited. These phenomena indicate that the residual surface charges left by the previous pulse should have a critical effect on the discharge dynamics of subsequent discharges. In order to have a deeper insight into the influence of residual surface charges in a repetitively pulsed SDBD, a numerical model characterized with a pre-charging of homogeneous charge accumulated on the dielectric surface is built. Pre-charging of positive charges deposited on the dielectric surface can inhibit the electric field of applied voltage, resulting in a decrease in the expansion of the primary streamer and the positive peak of current, which is in qualitative agreement with the experimental measurements. However, there is an opposite evolution rule when the negative charges are deposited on the dielectric surface. Although the electric field strength of the secondary streamer is enhanced for a high pre-charging value, there is no great impact on the negative peak of current during the secondary streamer due to the remaining heavy mass ions.