The “black barrier” phenomenon caused by plasma sheath during the reentry of a high-speed target will seriously affect the detection of radar echo by a ground monitoring station, which is not conducive to making corresponding adjustments to different situations in real-time. The echo reflects the information of the target's position and speed, which is significant for real-time monitoring and effective strike. In this work, the effect of a high-speed target plasma sheath on electromagnetic wave echo characteristics was investigated by using the proposed spatially inhomogeneous and time-varying plasma sheath model. The Z-transform finite-difference time domain (Z-FDTD) method was adopted to calculate the time domain and frequency domain results of the echo in plasma sheaths with spatially inhomogeneous, uniform and spatially inhomogeneous and time-varying electron density distributions. The effects of different time-varying parameters and plasma parameters on the echo characteristics of the plasma sheath were analyzed. The results show that the reflected echo in spatially inhomogeneous and time-varying plasma is less than that of the other two. The magnitude of the reflected echo is proportional to the time-varying parameter peak coefficient and Gaussian width, and inversely proportional to the collision frequency and plasma thickness. The theoretical results provide important guidance for ground monitoring and anti-stealth.

中文翻译：

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空间不均匀时变等离子体鞘层回波特性分析


高速目标再入过程中等离子体鞘层造成的“黑障”现象将严重影响地面监测站对雷达回波的探测，不利于实时针对不同情况做出相应调整。回波反映了目标的位置和速度信息，对于实时监测和有效打击具有重要意义。在这项工作中，利用提出的空间不均匀和时变等离子体鞘层模型研究了高速目标等离子体鞘层对电磁波回波特性的影响。采用Z变换时域有限差分(Z-FDTD)方法计算了空间不均匀、均匀和空间不均匀且时变电子密度分布的等离子体鞘层中回波的时域和频域结果。分析了不同时变参数和等离子体参数对等离子体鞘层回波特性的影响。结果表明，空间不均匀且时变等离子体的反射回波小于其他两种等离子体。反射回波的幅度与时变参数峰值系数和高斯宽度成正比，与碰撞频率和等离子体厚度成反比。理论结果为地面监测和反隐身提供重要指导。