The phenomenon of communication blackout encountered by reentry vehicles during reentry into the atmosphere has been extensively studied. This paper investigates the causes of the blackout phenomenon by analyzing the propagation characteristics of electromagnetic wave within the plasma sheath. Based on the typical RAMC-II vehicle model, the influence of different antenna installation locations on signal transmission is explored. Numerical analyses of collision frequency and plasma frequency at various positions are conducted to determine the optimal region for radio frequency (RF) signal transmission. Using simulated flow field data, the scattering matrix method, capable of solving non-uniform electron density distributions, is applied to evaluate the numerical impact of reentry velocity on RF signal input. The results demonstrate that appropriately reducing reentry velocity decreases both the collision frequency and plasma frequency, thereby enhancing RF signal transmittance. In addition, a chemical reaction model with 18 reactions of seven components is used to measure the mass fraction of the seven components at distances normal to the surface of the vehicle with the aim of exploring the chemical reactions that affect electron density. The theoretical findings presented in this study provide robust support for understanding the propagation of electromagnetic wave in plasma during vehicle reentry.
Zhang et al. (Tue,) studied this question.