Electromagnetic Wave Propagation And Scattering In Plasma Sheath

Electromagnetic wave propagation and scattering characteristics in plasma sheath is an important theoretical basis for solving the communication interruption in high-speed vehicles. During vehicle re-entry into the atmosphere or when flying in near space with supercritical speed, the surface of the vehicle is dissociated and ionized by the friction between the surface and the surrounding air. Thereby, a plasma sheath is formed. The plasma sheath is a serious disturbance to the communication between the vehicle and the outside environment, even leading to complete communication interruption. In this study, the FDTD method, phase screen theory, forest scattering model, and Monte Carlo method are used to investigate the propagation and scattering characteristics of electromagnetic waves in the plasma sheath. The highlights of the study are as follows:1. Problems of communication interruption in plasma sheath are introduced, and the significance of the study is introduced. Present situation and main contents of the paper are discussed.2. In this chapter, the formation mechanism and characteristic parameters of plasma sheath are summarized. These parameters are impact frequency, electron density, electrical conductivity, characteristic angular frequency, dielectric constant, and cyclotron frequency. Electromagnetic characteristics of the plasma sheath of the vehicle are described.3. Transmission and reflection characteristics of the electromagnetic wave on the basis of the principle of FDTD are shown through different thicknesses and layers of the layered plasma sheath. In addition, the influence of incident angle on the propagation of electromagnetic wave in the plasma sheath is analyzed by comparing the transmission and reflection coefficient at the different incident angles.4. Phase screen theory is applied to the plasma sheath. The Shakrofsky power spectrum is used in the plasma sheath, which is equivalent to the phase screen. The influence of the logarithmic amplitude attenuation and phase deviation of the electromagnetic wave with different flight heights, electron densities, and layered characteristics is investigated.5. Influence of the ablation of particles on the characteristics of electromagnetic wave scattering is examined by associating with the forest scattering model using Monte Carlo stochastic theory. In this paper, the surface of the aircraft is hypothesized to be a rough surface. Based on this hypothesis, the influence of the ablation layer on the scattering coefficient of electromagnetic wave is discussed with Fresnel reflection theory.