| Summary: | The plasma sheath formed during the reentry process is able to block the detection and communication to the hypersonic vehicle. Various of interactions occur during the propagation of EM wave in the plasma sheath. In addition, the dusty particles formed during the ablation of the protective layer make this process more complicated. Dusty plasma sheath is an important factor that affect the detection of hypersonic vehicle. In this work, the propagation properties of THz wave in inhomogeneous dusty plasma sheath are studied. The flow field distribution around the hypersonic vehicle is simulated first. Then the electron density is calculated using equilibrium constant method of the 7-species reacting air model. And the collision frequency is calculated based on the results of the flow field simulation. The absorption and scattering process are studied using scattering matrix method and Mie scatter theory, respectively. The propagation properties are calculated considering the influences of the flight speed, the flight altitude, the radius, the number density and the kind of the ablation particles. The calculation results show that with the increase of THz wave frequency, the transmittance increases firstly and then oscillates. The shape of the transmittance curve is determined by the flight speed, the flight altitude, the radius, the number density and the kind of the ablation particles. The main loss mechanisms in different wave bands has also been discussed and the optimum transition band is given. This work shows that THz wave has good potential applications in hypersonic vehicle detection. It also provides a method to select the optimum detection frequency band.
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