A Prospective of Plasma Actuators in Aerospace Engineering

The effectiveness utilizing plasma as a working medium for viable aerospace applications beyond electric propulsion and thermal protection for earth reentry were summarized and assessed. The analysis was based on the intrinsic properties through Joule heating, electrostatic force, Hall effects, and Lorentz acceleration. The plasma actuator has been implemented for the entire aerodynamic domains from subsonic to hypersonic flows and in the rarefied and continuum regimes. It is truly remarkable that the electromagnetic force and energy in applications are involved only on a perturbation level in comparison with the flow field to be modified. Hence, the effectiveness of flow control is limited at aerodynamic bifurcations such as the point of flow separation, hydrodynamic instability, dynamic stall, and vortex breakdown. Creditable applications often have to amplify by viscous-inviscid interaction, externally applied magnetic field, and microwave energy transfer to increase its effectiveness. Based on these assessments, future basic research innovations were offered to the last few scientific research frontiers.