等离子体鞘套中的电波传播特性研究

采用压力权函数修正的迎风型矢通量分裂格式（AUSMPW+），求解纳维-斯托克斯（Navier-Stokes）方程组，得出不同飞行速度下等离子鞘套内的电子密度分布。基于改进的文策尔-克拉莫斯-布里渊（WKB）方法分析了电磁信号经过等离子鞘套的幅频特性，同时还给出了电磁波在鞘套中传输的相频曲线、群时延特性曲线。计算结果表明：随着飞行器速度增大，鞘套内电子密度增加，电波衰减明显增大，且电磁波在等离子鞘套中传输的相频特性受等离子体频率以及碰撞频率影响，在等离子体频率附近群时延最大。

EM wave propagation characteristic in plasma sheath

The Navier-Stokes equations are solved in this paper by using the AUSMPW+ scheme and the electron density distribution in the plasma sheath is given at different flight speeds.Based on the modified Wentzel-Kramers-Brillouin method(WKB) method,the amplitude-frequency characteristics of electromagnetic signals are analyzed and the phase-frequency curve and the group delay curve are also presented.Numerical result shows that the faster the vehicle speed is,the higher the electronic density is,and attenuation coefficient increases.The phase frequency characteristics of radio wave in the plasma sheath are affected by the collision frequency and plasma frequency.The group delay reaches the maximum near the plasma frequency.