深空核爆电磁脉冲壳模型下的电子运动规律

Analysis of electron motion in case signal model for electromagnetic pulse generated by detonations in space

采用壳模型分析了深空核爆的电子运动规律,对深空核爆电磁脉冲的形成机理进行了初步研究。考虑MeV量级出射电子的相对论效应,在相对论框架下进行了电子运动过程的推导。计算了空间电荷层限制的形成时间,并提出一旦形成空间电荷限制,后续状态满足准静态近似条件。在此基础上,推导了空间电荷振荡的频率,并与半数值计算的结果进行比对,二者符合得较好。计算表明,远场达到峰值的时间与爆炸当量、电子初始动能和弹体半径等参数密切相关,电场峰值总是出现在核反应极大值之前,并且在空间电荷层限制的形成时间附近。

Applying the case signal model,a preliminary understanding of electromagnetic pulse（EMP） generated by detonations in space has been developed in this paper.Taking into account of the relativistic effects,recalculation of the formation time of the space charge limit was accomplished which suggested that once the space charge was formed,the system could be treated as in the quasi-steady situation.Based on that point,frequency of the space charge oscillations has been analytically derived and semi-numerically calculated.The results agree with each other very well.For observers in large distances,a net dipole moment can be resulted from the average movements of space charges.Calculations indicate that the peak value of the radiation signal in the far field always appears before the maximum time of nuclear reactions and is close to the formation time of the space charge limit.