强激光靶耦合过程中激发的电磁脉冲诊断与分析

本文论述采用脉冲天线对激光靶耦合过程中产生的电磁脉冲信号进行采集,列举了在相同条件下,纳秒激光与几种靶相互作用激发的电磁脉冲信号,分析了靶型对电磁脉冲信号的影响,得出靶的对称性设计有助于抵消靶室内的电磁干扰的结论。并且,通过测量靶室内与靶室中心不同距离区域的电磁脉冲信号,总结出电磁脉冲在靶室内的传播规律。由于靶室内回波振荡的作用,随着远离靶室中心,脉冲幅值先减小,后增大。且随着距离增大,越靠近靶室内壁区域受到回波振荡的影响越大,进而导致电磁脉冲持续时长增大。通过回波振荡论证测试与屏蔽实验,得出回波振荡在靶室内电磁脉冲信号中占有较大比重的结论。诊断设备的安放应尽量避免靶室中心与靠近靶室内壁区域。

Measurement and Analysis of EMP Generated from the Interaction between Laser and Target

Electromagnetic pulse (EMP) radiating from the interaction when ultra-intense laser irradiated the target was captured by pulse antennas. This paper listed EMP signals from the interactions of nanosecond laser with several targets at the same condition to compare and figure out the effect of target type. Conclusion came out that symmetric targets contributed to the counteraction of electromagnetic interference inside the target chamber. In addition, distance from target chamber center (TCC) was taken into consideration to figure out the transmission regular of the EMP. Along with the increase of distance from TCC, the EMP amplitude decreased first, and then increased, due to the effect of backward-wave oscillation inside target chamber. Also, area closing to the chamber wall sustained more from backward-wave oscillation, resulting in the longer EMP duration. The backward-wave oscillation was demonstrated to occupy a large proportion of the EMP signal inside chamber by argumentation test and shielding experiment. Diagnostic equipment should not be installed in the area near to target chamber center or interior wall.