Temporal evolution of a surface dielectric barrier discharge for different groups of plasma microdischarges

We have experimentally investigated the properties of microdischarges originating in asymmetric surface dielectric barrier discharges fed by a high-voltage sinusoidal low-frequency drive. Devices exploiting such a configuration are currently proposed as plasma actuators, because they induce a directed airflow in the gas surrounding the surface. Light emission and electric current associated with individual microdischarges have been recorded with high temporal resolution. A statistical analysis of the dataset was performed to correlate microdischarge properties with the voltage phase and to spot peculiarities arising from the actual breakdown mechanism in such a configuration. In particular, we demonstrated the asymmetry between the two different semi-cycles of the discharge, which could affect plasma actuator efficiency. Differences arising in the multiplicity, amplitude, temporal duration as well as in the spatial pattern of the discharge emitting region also permitted identifying several different groups of microdischarges, presumably playing different roles in both the discharge dynamics and airflow induction.