等离子体鞘套对飞行器再入过程信号传播特性的影响分析

再入飞行器表面所形成的等离子体鞘套会对通信信号的传播产生影响，甚至形成通信黑障。文章从电磁波在等离子体中的传播理论出发，分析建立鞘套对电磁波吸收和反射的数学模型；并以数学模型为基础，编制面向对象的计算软件，考察影响通信信号传播特性的各种因素。结果表明，等离子体鞘套内的电子密度及其分布对通信信号的传播特性有重要影响，减小等离子体密度可显著降低信号的衰减。

Analysis of characteristics of reentry sheath and its effects on communication

Plasma sheath surrounding reentry vehicle influences the transport of the communication signal, even the results in the communication blackout. The characteristics of the reentry plasma sheath are analyzed in this paper. Based on the theory of the wave propagation in the plasma and with consideration of the inhomogeneity of the electron density in the reentry sheath, a model is built to investigate the reflection and the absorption of the electromagnetic wave by the sheath. With the model, an object-oriented software is developed to calculate the reentry communication blackout and to investigate the factors that determine the communication blackout. It is shown that the plasma electron density and its distribution determine the transport of the communication signal. In a certain range of the plasma electron density the blackout effect exists, and it can significantly weaken the signal attenuation to decrease the electron density.