关键词: 高超声速飞行器, 等离子体鞘套, 激波管, 微波, 传输特性

Abstract:

In response to the need for research on anti-blackout of high-speed aircraft， plasma sheath simulation and comparative analysis are carried out. The multi-functional shock tube is selected as the ground simulation equipment for plasma sheath simulation around high-speed aircraft. The propagation characteristics of L/S/C/Ka band microwave in simulated plasma sheath are tested. The propagation attenuation characteristics of microwave in the experimental plasma are calculated by the ADE-FDTD method and the thin layer propagation method. In the calculation， the measured values of electron density and collision frequency are used. The influence of frequency band， plasma electron density and collision frequency on transmission characteristics of microwave are obtained. The results show that when the plasma layer thickness is more than several times the wavelength and the collision frequency is not too high， the propagation characteristics of electromagnetic wave in plasma are in good agreement with the prediction results of plane wave theory. In the region where the plasma frequency， electromagnetic wave frequency and collision frequency are close to each other， the measured results of electron density and collision frequency have great influence on the theoretical analysis of electromagnetic wave propagation characteristics. When the plasma thickness is larger than the electromagnetic wave length， the predicted results of thin layer propagation method are quite different from the experimental ones. When the plasma thickness is less than the electromagnetic wave length， the difference between the predicted results of the thin layer propagation method and the experimental data is obviously reduced， and the trend of similarity between them is high.

Key words: hypersonic vehicle, plasma sheath, shock tube, microwave, propagation characteristic