Simultaneous formation of striations and patterns in surface dielectric barrier discharge

Longitudinal striations and transverse patterns are simultaneously observed in a surface dielectric barrier discharge (DBD) system in argon. Patterned filaments form at sufficient high frequency and moderate voltage. The images of bright filaments and faint regions between them reverse alternately in the two half-cycles. The number of luminous filaments is generally determined by the gas pressure rather than the applied voltage. The striations appear during the plasma expanding above the anode surface in negative half-cycle, in the filaments as well as the regions between them synchronously. The striation spacing does not depend on the voltage, but decreases with the gas pressure in the present configuration. The formations of striation and pattern are two separated processes, and both relate strongly to the accumulated charges on the dielectric surface and the induced surface field.