电离层对电磁脉冲传播的影响可以用一个频域的电流密度来描述, 在时域则等效为一附加的电流密度和电导率。推导了附加电流密度和电导率在时域的表达式, 它们是电离层参数和作用电场的函数, 并以差分方程的形式给出。高空核爆电磁脉冲(HEMP)的计算是在时域进行的, 将该电流密度和电导率计算方法应用于HEMP产生和传播的自洽计算中。作为算例, 计算了100 km高空核爆电磁脉冲产生和向上传播的3种情况, 并对计算结果进行了比对分析。计算结果表明: 电离层时域计算方法与核爆电磁脉冲计算方法的结合是合理有效的, 爆点上方考虑电离层影响的HEMP要比不考虑电离层影响的结果小得多。

Additional current density, which is a function of frequency, can be used to describe the effect of the ionosphere in the process of electromagnetic pulse propagation. In time domain, however, this effect can be expressed in two terms: current density and conductivity. Their time-domain expressions were derived in differential equation forms, which are the functions of ionosphere parameters and the electric field exerted. These current and conductivity were used directly in the high altitude nuclear electromagnetic pulse(HEMP) calculations, for which these computations need to be held in time domain to simulate the HEMP stimulation and propagation in the ionosphere simultaneously. As an example, three cases of the stimulation and propagation of HEMP exploded at a height of 100 km were calculated. Comparison and analysis of the results show that the computation methods are reasonable and effective, and the amplitude of HEMP above the burst point influenced by the ionosphere is much smaller than that not influenced.