Surface Potential and Electric Field Structure in the Aerodynamic Plasma Actuator

Abstract

We present the results obtained by adapting a passive measuring technique, namely the capacitive V-dot probe, to the surface discharge mode single dielectric barrier discharge aerodynamic plasma actuator to obtain the spaceand time-varying potential at the dielectric surface. From these data, we can infer information about the longitudinal electric field in the plasma. We find that the potential at the surface is primarily determined by the deposition of charge on the surface, and only secondarily by capacitive voltage division in the actuator structure. We find that the distribution of charges on the surface settles very quickly (within one to a few AC cycles of the high voltage applied to the device) into an equilibrium configuration. We find that this equilibrium varies with the specific capacitance of the actuator and with the frequency of the applied voltage, but not with the surface properties of the dielectric material. We conclude that the equilibrium condition is driven by the necessity that the AC cycle including the forward and backward strokes of the discharge be charge neutral, even though the nature of the discharge between these two phases of the discharge is very different.