Propagation characteristics of terahertz wave in inhomogeneous dusty plasma sheath considering scattering process

Abstract

The dusty plasma sheath formed during the reentry process of hypersonic vehicle will interrupt the propagation of the communication signals, which is called the blackout problem. One of the most effective solutions to the blackout problem is to detect with terahertz wave, which refers to the electromagnetic wave with a frequency range from 0.1 to 10THz. Recently, the propagation characteristics of terahertz wave in dusty plasma have been studied based on the analyzed of the dielectric properties. Unfortunately, the influence of scattering caused by ablation particles is neglected in these studies, which can be ignored no more, especially for high terahertz wave. In this work, the propagation characteristics of dusty plasmas are analyzed considering both intrinsic absorption and scattering. Firstly, the electron densities and collision frequencies have been calculated based on the simulation of flow field around a return capsule model, and then the dielectric properties are analyzed. Secondly, the propagation characteristics are calculated and the results show that with the increase of detection frequency, the transmittance of THz wave in dusty plasma increases due to the decrease of absorption. But for higher frequency, the stronger scattering leads to the decrease of transmittance. Moreover, the influences of the flight speed of the vehicle, the diameter and density of ablation particle are also discussed. This research provides a basis for the selection of the best frequency band for the detection of return capsule.