Effects of different flight conditions on terahertz wave propagation in a realistic plasma sheath

Abstract Investigating terahertz (THz) communication under varying flight conditions is crucial for guiding flight control and Radio Frequency (RF) blackout during reentry. This paper integrates hypersonic fluid dynamics models with THz wave propagation simulations to model the distribution of electron density, collision frequency, and electron temperature in reentry flow fields under typical flight velocities, altitudes, and angle of attack (AOA). The variations in THz wave propagation characteristics in the rear region of the vehicle under these conditions are analyzed, along with the underlying mechanisms. The results show that increasing reentry velocity and decreasing altitude lead to higher electron densities and reduced power transmission rates. Variations in the AOA cause fluctuations in the peak values of electron density and electron temperature, with THz wave transmission rates increasing as the AOA increases. The paper determines the cutoff frequency of the antenna along the axial direction of the vehicle ( l = 0.9 m) to be above 0.065 THz and demonstrates that optimizing flight velocity and AOA can enhance the received THz signal strength. These findings provide theoretical guidance for communication optimization and RF blackout mitigation in hypersonic vehicles.