Analysis on the Characteristics of EM Waves Propagation in the Plasma Sheath Surrounding a Hypersonic Vehicle

The plasma sheath surrounding a hypersonic vehicle will cause severe interference to the wireless communications and even interrupt the communications, threatening the flight safety. To better understand and mitigate the interference of the plasma sheath to electromagnetic (EM) wave propagation, the interaction mechanisms between them are studied in this paper. First, using the COMSOL multiphysics software, the flow field of the plasma sheath is simulated, from which the EM parameters are obtained. The plasma sheath is then separated into three zones with different behaviors of the electron density profile. Finally, combining the theory of the EM wave propagation in the plasma, ray tracing equations are solved numerically to observe the EM wave propagation characteristics in the plasma sheath. On this basis, some special propagation characteristics result, such as the directional characteristic of the wave propagation and the “waveguide” behavior of the plasma sheath, which are then explained using the geometrical optics theory. The results obtained in this paper are expected to be able to provide some new applications for wireless communications during hypersonic flight, and to further advance the research related to this subjects.