湍流等离子体尾迹雷达散射截面的计算及其影响因素分析

针对一阶畸变波Born近似模型,深入分析了湍流内外尺度和电子数密度脉动值对雷达散射截面的影响,并且给出了关于湍流外尺度的一个经验的,能被工程上较好使用的公式.在以上分析的基础上,计算了几种高程条件下再入小钝头锥体等离子尾迹的雷达散射截面,与已有实验结果进行了对比分析.分析和计算结果表明,湍流的外尺度和局部电子数密度值对雷达散射截面值影响较大;湍流内尺度变化的影响不大.

Calculation of radar cross section of the reentry wake turbulence and analysis for the characteristics

The precision of calculation of radar cross section (RCS) of a reentry vehicle, which is surrounded by the underdense turbulent plasma, is determined by the accuracy of the computation results on the characteristics of turbulent flow and electromagnetic field. Those characteristics are affected greatly by various complicated factors. In the present paper, the effects of inner scales, outer scales and electron density fluctuations in flow field are studied for the RCS calculation with the first order distorted wave Born approximation model. Based on the analysis, a practical and empirical formula for outer scales of turbulence is proposed. And the RCS at different altitudes are calculated, and compared with experiments. The results show that the effects of outer scales of turbulence and electron density fluctuations are important in the calculation of RCS, and that the effect of inner scales of turbulence can be ignored.