Mechanisms and responses of a single dielectric barrier plasma actuator: Plasma morphology

We present simultaneous optical, electrical, and thrust measurements of an aerodynamic plasma actuator. These measurements indicate that the plasma actuator is a form of the dielectric barrier discharge, whose behavior is governed primarily by the buildup of charge on the dielectric-encapsulated electrode. Our measurements reveal the temporal and macroscale spatial structure of the plasma. Correlating the morphology of the plasma and the electrical characteristics of the discharge to the actuator performance as measured by the thrust produced indicates a direct coupling between the interelectrode electric field (strongly modified by the presence of the plasma) and the charges in the plasma. Our measurements discount bulk heating or asymmetries in the structure of the discharge as mechanisms for the production of bulk motion of the surrounding neutral air, although such asymmetries clearly exist and impact the effectiveness of the actuator.