Evolution of three-electrode pulsed surface dielectric barrier discharge: primary streamer, transitional streamer and secondary reverse streamer

The streamer evolution of three-electrode pulsed surface dielectric barrier discharge (SDBD) in atmospheric air is studied with basic morphologic features, electrical characteristics and numerical simulation. Time resolved ICCD images demonstrate that besides the primary and secondary reverse streamers, a novel discharge mode-transitional streamer is also responsible for sustaining the streamer development in the three-electrode pulsed SDBD, which is different from the streamer mechanism in traditional two-electrode pulsed SDBD. Moreover, the discharge mode transition from the primary streamer to the transitional streamer is observed in a relative narrow discharge gap of 5 mm, while a relative large discharge gap of 19 mm results in a new phenomenon in which the primary streamer transits to the secondary reverse streamer without the process of transitional streamer. To determine the deposited energy of each streamer phase, an equivalent circuit model is built and it shows that the transitional streamer possesses the main energy. To make a further understanding of the formation and propagation of three streamer phases, a 2D fluid model is implemented and the streamer evolution and species distribution are analyzed. The results exhibit that the gathered positive ions in primary streamer head does not move forward when it is close to the second grounded (SG) electrode surface, because the same positive polarity of a cathode layer is formed on the SG electrode surface.