Study on Discharge Dynamics in an Atmospheric Pressure Dielectric Barrier Discharge

In this work, the discharge dynamics in an atmospheric pressure dielectric barrier discharge (DBD) is studied in a DBD reactor having parallel plate electrodes geometry. The DBD reactor is powered by a 50 Hz ac high voltage power source through a ballast resistor. The images of filaments occurring in the discharge gap are captured using a high speed intensified charge coupled device camera. The occurrence of frequent synchronous breakdown of micro discharges has been observed across the discharge gap when the electron avalanche happens in the direction from the dielectric surface towards the opposite electrode. The discharge gap dependence on synchronous breakdown is studied by changing the discharge gap. The shape of the filaments has been found to be strongly dependent on the direction of the electron avalanche. It is demonstrated that the diffusion of electrons occurs when the electron avalanche happens in the direction towards the dielectric from the opposite electrode. A smaller diffusion leading to narrower filaments is observed when the electron avalanche happens in the direction from the dielectric to the opposite electrode. This can be explained by the existence of memory charge on the dielectric surface.