Parameterization of temporal structure in the single-dielectric-barrier aerodynamic plasma actuator

We present the results of two measurements that describe the interaction of an aerodynamic plasma actuator (a dielectric barrier discharge plasma in which an asymmetric arrangement of electrodes leads to momentum coupling into neutral air) with the surrounding atmosphere. We show that the presence of oxygen in the Earth's atmosphere plays a substantial role in the efficiency of the actuator. We measure the time-resolved neutral air density in the vicinity of the actuator using a laser beam probe. We show that the effect of the actuator is to establish a region of increased neutral density in the vicinity of its exposed electrode's edge, and we show that the actuator couples directed momentum into the air by pulling air up-this density, gradient, against the corresponding pressure, and releasing it in the downstream direction when the plasma quenches, replacing it with air from the volume above the actuator. These measurements harmonize previously contradictory measurements of the actuator's behavior.