中文摘要：

基于电流密度拉普拉斯变换方法改进的时域有限差分（LTJEC-FDTD）算法,研究时变等离子体目标的电磁散射特性.由Maxwell方程和等离子体本构方程出发,利用拉普拉斯变换和拉普拉斯逆变换,推导出计算三维时变问题的时域有限差分（FDTD）算法的迭代式.采用模式匹配方法验证了FDTD迭代式的正确性,并通过计算等离子体球的雷达散射截面（RCS）验证了算法相关边界的正确性.最后用LTJEC-FDTD算法分析了涂覆时变等离子体的战斧式巡航导弹的RCS.

英文摘要：

To analyze the time-varying plasma,a modified finite-difference time-domain（LTJEC-FDTD）algorithm is derived.By using Laplace transform and inverse Laplace transform,we can deduce the FDTD iteration expression for calculating 3D time-varying problem from Maxwell equation and plasma constitutive equation.The iteration expression is proven to be correct by mode-coupling theory,while the correctness of the relevant boundary is tested by calculating the radar cross-section（RCS）of plasma sphere.So,the method is suitable to the calculation of time-varying plasma.Then,the RCS of complex time-varying plasma object is also analyzed.