Ionization wave Propagation in Nanosecond Pulsed Discharge and its Application*

Surface dielectric barrier discharge (SDBD) at atmospheric pressure driven by high-voltage nanosecond pulses has been a promising discharge form, which has its potential application in plasma flow control and the plasma assisted ignition and combustion. The breakdown process of the nanosecond pulsed SDBD is generally accompanied by a discharge propagation along the dielectric surface, which is usually called the surface ionization wave (SIW). An investigation of the SIW is valuable for both a deeper understanding of the atmospheric pressure discharge and an improvement of its plasma application.

In this work, the propagation of the surface ionization wave in the nanosecond pulsed surface dielectric barrier discharge with different dielectric materials and pulse repetition rates is investigated. The current waveforms at different locations along the route of the SIW propagation are obtained, based on a specially designed ground strip array geometry. The temporal evolution and spatial distribution of the electric field during the SIW propagation are measured by using the electric field induced second harmonic (EFISH) generation method. It is found that with the dielectric material on which the surface charges decay faster, there are the well-pronounced primary and secondary SIWs with a higher velocity on the voltage rising edge and both the peak current and the peak electric field are also higher, with a less spatial attenuation along the SIW propagation route. It is demonstrated that the residual surface charges with the same polarity as the high-voltage pulse suppress the development of the surface ionization wave.