Formation of striations in large-gap coplanar dielectric barrier discharge

Striations in a large-gap coplanar dielectric barrier discharge (DBD) have been investigated by experiment and numerical simulation. The discharge current was measured and the images of infra-red (IR) radiation striation were obtained by an intensified charge-coupled device (ICCD) camera with nanosecond exposure time. The discharge processes are simulated by particle-in-cell/Monte Carlo collision (PIC/MCC) code. The calculated current and the distribution of Xe ^* during a single pulse were compared with the experiment. The results show that there are two series of striations corresponding to two stages of discharge. The striations of the second stage are generated as the potential changed remarkably, while the distribution of surface charge almost keeps unchanged. The electric field induced by the space charges plays a key role in the formation of the striations. The stratified wall charge is only a consequence of the stratified spatial field and the striations.