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

摘要

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-l 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.