超高速飞行器气动外形对电波传播特性的影响

等离子体鞘套会对飞行器的无线通信信号产生强烈的干扰，甚至中断信号而威胁飞行器的飞行安全．为了解不同气动外形对电波传播特性的影响，文中研究了典型飞行器外形(钝头和尖头)外部鞘套的电波传输特性．首先，采用商业软件COMSOL计算不同飞行条件下的流场分布，生成离散鞘套模型数据．然后，结合等离子体中电波传播理论，采用高维Lagrange插值以及Runge-Kutta等方法数值地求解电波在鞘套中的射线方程，得到电波轨迹和衰减以及一些新的传播特性，并对这些传播特性的物理机制进行了分析．结果表明，在相同条件下，钝头飞行器对电波的干扰明显地强于尖头，表现出丰富的传播现象．取得的这些结果，能够为超高速飞行器设计提供参考，并进一步推动相关问题的研究．

Influence of the aerodynamic shape of a hypersonic vehicle on characteristics of EM wave propagation

The plasma sheath surrounding a hypersonic vehicle will have a severe interference on the wireless communication signals and even interrupt the signals, threatening the flight safety. The plasma sheath is closely related to the vehicle's shape which indirectly affects the propagation characteristics of the radio waves. For understanding the influence of different aerodynamic shapes on the wave propagation, the EM wave propagation in the plasma sheath produced by aircraft, including blunt and pointed cone, is investigated. First, the commercial software COMSOL is used to calculate the flow field distribution under different flight conditions, generating the discrete model of plasma sheath. Then, according to the wave propagation theory in the plasma and using the Lagrange and Runge-Kutta methods, ray equations in the plasma sheath are solved numerically, which results in observing some new characteristics of wave propagation, such as waveguide behavior. The results show that, under the same conditions, the interference caused by the blunt vehicle is stronger than that by the pointed vehicle. These results can provide references for the design of hypervelocity aircraft, and further promote the study of related issues.