Surface potential distribution and surface charge behavior in a plane-parallel DBD in atmospheric air

Dielectric barrier discharges (DBDs) have been applied in a wide range of applications such as ozone generation and air flow control. In many cases of a DBD, microdischarges (MDs) often occur, which are filamentary discharges with extremely short current pulse widths (a few tens of ns), and numerous MDs are randomly distributed on the dielectrics due to the influence of residual surface charge. Thus, surface charge could be a key to control the performance of DBD applications. In this study, we measured the electrical potential on the dielectric in a DBD occurred in a parallel plate electrodes configuration in atmospheric air using the Pockels effect [1]. We applied a 5 kHz sinusoidal high voltage of several kV between parallel plate electrodes, where Bi4Ge3O12 (BGO) crystal is set between the electrodes with a gap length of less than 1 mm and generated multiple discharges. The Pockels effects were observed with a high-luminous LED and high-speed camera to obtain the spatiotemporal variations of the dielectric surface charge. The measurement of the surface potential showed that external voltage magnitude contributes to spatial memory effect of MD and diffusion of the surface charge.

[1] Mitsuhashi K, et al., Plasma Sources Sci. Technol. 30 04LT02(2021).