Range Profile Analysis of Hypersonic Vehicles Covered by Inhomogeneous Plasma Sheath Using Physical Optics

Using the parallel physical optics method, the range profile of a hypersonic vehicle with an electrically large size covered by 1-D inhomogeneous plasma sheath was studied. In this article, under the condition of far-field approximation, the improved physical optical method of 1-D nonuniform plasma coating of the conductive target was applied to calculate the scattered electric field of the target at different frequencies; then, 1-D Fourier inversion of the scattered electric field was carried out to obtain the 1-D range profile of the target. Numerical results showed that the temperature and pressure changes inside the plasma will have an impact on the range profile of the aircraft, and the intensity of the range profile of the target is inversely proportional to the temperature and pressure. In addition, the flight Mach parameters of the target aircraft, which affect the 1-D range profile, were also analyzed. The results showed that the larger the flight Mach number, the easier it is to detect the target aircraft. Finally, it was found that the nonuniformity of the plasma significantly influenced the 1-D range profile of the coated target; the intensity value of the range profile of the target aircraft (covered by the plasma sheath) at different flight heights was significantly lower than that of the pure metal target, resulting in the so-called “stealth” effect. This research provides some methods for effectively measuring and controlling hypersonic vehicles in adjacent space and alleviating the interruption of reentry communication.