Plasma actuator with arc breakdown in a magnetic field for active flow control applications

Recent work investigated an innovative plasma-based flow control actuator which produces a high-voltage plasma arc across a coaxial pair of electrodes positioned within the field of a strong rare-earth ring magnet. Generation of the plasma arc within a magnetic field perpendicular to its current path results in a Lorentz force on the charged particles, causing the arc to sweep about the center of the coax, forming a plasma disc. Being similar in concept to microwave-generating cyclotron elements, the resulting actuator concept has been designated as a “Cyclotronic Plasma Actuator”. The innovative aspect of this concept is the coupling of the thermal actuation of the plasma arc along with the induced swirl component produced by the angular velocity of the Lorentz forcing. This actuator is envisioned to be used in boundary layer flows when the coaxial arrangement is embedded in an aerodynamic surface. The purpose of the device is to alleviate turbulent flow separation, serving as a controllable vortex generator that can be enabled or disabled on-demand (e.g. during takeoff and landing), and also does not produce parasitic drag during high speed cruise. Demonstration of this technology in the current program pioneers a class of plasma actuators aimed at addressing a notorious problem in active flow control.