Surface Potential and Longitudinal Electric Field Measurements in the Aerodynamic Plasma Actuator

We present the results of a series of measurements in which an array of capacitive V-dot probes are used to determine the surface potential in a single dielectric barrier discharge plasma operated as an aerodynamic plasma actuator. From these measurements, we determine the longitudinal electric field in the plasma. The results show that the surface immediately (within the first alternating current cycle of the plasma discharge) acquires a net positive surface charge, so that the electric field in the plasma is asymmetric, the magnitude of the maximum field being more than 50% larger in the negative than the positive polarity. The measurements also show that there is a region several millimeters downstream from the exposed electrode edge over which the electric field maintains a constant positive (downstream) polarity over the course of the discharge cycle.