The 2D imaging study of plasma sheath and wake

When a high-speed aircraft flies through the atmosphere, the plasma sheath and plasma wake can significantly affect electromagnetic wave signals. To investigate the impact of the plasma sheath and wake on radar imaging, this paper first develops a linear frequency modulated continuous wave radar array signal echo model for the full target (body, plasma sheath, and plasma wake). The model effectively considers the spatial distribution characteristics of the dielectric constant and velocity in the plasma flow field. Subsequently, 2D range-Doppler images and 2D range-angle images of full targets were studied, using a joint range-velocity-angle estimation algorithm at different frequencies and altitudes. The research results show that at an altitude of 40 km, with incident frequencies from 1 to 3 GHz, the signals of the body and its wake are stronger at 1 GHz, which is favorable for full target imaging. In contrast, at 3 GHz, the wake signals are obviously weakened, allowing the body to be extracted almost separately, which is more favorable for target identification and tracking. Similarly, at 1 GHz, the wake signal gradually weakens as the altitude increases from 40 to 70 km. At 40 km, the full target is imaged more clearly. Furthermore, under the conditions of this paper, the variation of parameters has a smaller effect on the angle direction and a larger effect on the range direction. This research provides a theoretical basis for the improvement of radar detection technology, especially in the plasma environment, which provides a valuable reference.