高功率激光装置电磁环境研究进展

激光惯性约束聚变研究中,高功率激光器靶室中强激光-靶物质作用产生的高能电子的运动、X射线与周围物质作用产生的置换电流将激励出强电磁脉冲,场强幅值高达几万V/m,频率达GHz量级,能库等工作区域大电流、大电压的快速变化过程也将辐射电磁场,这些电磁脉冲对电子设备将产生各种电磁耦合效应,影响控制时序、测量数据的准确性,严重的甚至使仪器设备毁坏,这种电磁脉冲对生物组织具有损伤效应。本文详细介绍了国内外高功率激光装置电磁环境的理论与实验研究进展情况。     

Simulation of electromagnetic pulses generated by escaped electrons in a high- power laser chamber

Intensive electromagnetic pulses (EMPs) can be generated when a high-power laser strikes a target. The transient electromagnetic field can have an intensity of up to several hundred kV m ^-1 with a broad frequency of up to several gigahertz, which may affect diagnostics and interfere with, or even damage, electronic equipment. In this paper, the process in which hot electrons produced by the laser-target interaction radiate EMPs is studied and simulated. The physical process is divided into three stages which are: the production of hot electrons; the escape of hot electrons; and the generation of EMPs. Instead of using a general finite difference time domain (FDTD) method to solve the Maxwell equations, a particle-in-cell method together with a time- biased FDTD method is applied in EMP simulation to restrain high-frequency noise. The results show that EMPs are stronger with higher laser intensity and larger target size.     

电磁脉冲模拟器快前沿高压脉冲源设计

为给强电磁脉冲模拟器提供快前沿高电压能量以形成符合标准的强电磁脉冲环境,文章开展了对模拟器核心部件——700 kV高压双指数脉冲源的设计工作。基于Marx发生器和一级峰化技术,将脉冲压缩形成快前沿高压脉冲对天线负载放电,输出波形上升前沿小于2.5 ns,半高宽大于23 ns。通过电路仿真对比不同元件参数对脉冲源输出波形的影响,确定主要部件的参数设计目标后开展了高压脉冲源的设计和研制。详细介绍了脉冲源主要部件Marx发生器和峰化电路的设计过程、参数预估和测量情况,给出了脉冲源产生的双指数电压波形。试验结果表明,该快前沿高压脉冲源的输出波形满足设计指标,可以通过双锥天线在较大区域形成脉冲电场,用于强电磁脉冲环境模拟装置。