惯性约束聚变(ICF)背景下的激光靶耦合过程产生大量电磁脉冲, 对诊断设备的正常运行和测试数据的采集产生不良影响, 严重时甚至损害诊断装置。介绍了强激光与金属靶相互作用过程中受激辐射产生等离子体的数学模型, 模拟了盘锥脉冲天线的物理模型、三维增益等各项指标, 并对打靶过程进行测量, 得出电磁辐射电场值, 并推导出其频域分布。实验结果显示, 影响电磁辐射强度的因素有激光能量、激光打靶方式和入射方向等。对于平面靶, 相同靶型和靶材质情况下, 不同功率激光与平面靶相互作用发出的电磁脉冲具有相似的频谱和相同的特征频率。诊断结果为激光打靶产生电磁脉冲物理机制研究提供重要实验依据。

Massive electromagnetic pulses could be generated by the interactions between intensive laser and solid targets in inertial confinement fusion(ICF), leading to the inaccuracy of experimental data and even the malfunction of diagnostic facilities. A method for diagnosing electromagnetic pulses(EMP) generated by laser illuminating solid targets was presented. A conical antenna was designed and simulated to obtain the attenuation coefficient, 3D gain and other parameters of the antenna physical model. The in situ monitoring the target process was performed to evaluate the value of electromagnetic radiation and electric voltage, by which the time-domain distribution of electromagnetic impulse was expected. The experimental results indicate that the intensity of electromagnetic radiation is related to many factors, such as the power of laser, the way of laser shooting, and angle of incidence. As for planar targets, if image and material are the same, EMP engendered by laser with different power has the similar energy spectral density(ESD) and the identical characteristic frequency. The results are expected to offer significant experiment information to study physics mechanism regarding the interactions between laser and target, which will also lay foundation for the later EMP shielding design for the important diagnostic facilities in ICF experiment.