| Abstrakt: |
Dielectric-barrier-discharge plasma actuators have become very popular during the last decade. In aerodynamics, they have been employed for drag reduction, stability improvement, turbulence control, and so on. In this paper, the radar cross section (RCS) of a plasma slab and, moreover, an extra reflection from plasma actuators because of the Bragg diffraction are investigated. It was observed that plasma actuators operating in lower altitude conditions produce plasma with a very high collision rate and low electron density. Under these conditions, the dielectric properties of the plasma are not discernable from the air. As a result, at high pressure, the actuator has no significant effect on RCS. In contrast, for higher altitudes, the air pressure decreases, so electron lifetime increases and collision rate reduces, so the effect of plasma on incident electromagnetic wave can be observed. In addition, the use of conventional plasma actuators being used in aerodynamics makes more reflections at specific incident angles because of the Bragg diffraction. This angle depends on the frequency and the spatial period of the actuator. [ABSTRACT FROM PUBLISHER] |
