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...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.展开更多
Long-strip multi-gap resistive plate chamber(LMRPC) were built with(Module 1) or without(Module 2) adhesive tapes and silicones.Their performances were investigated by working gas mixtures of different gradient conten...Long-strip multi-gap resistive plate chamber(LMRPC) were built with(Module 1) or without(Module 2) adhesive tapes and silicones.Their performances were investigated by working gas mixtures of different gradient contents(Test 1:94%freon,5%iso-butane and 1%SF_6;Test 2:90%freon,5%iso-butane and 5%SF_6).Both the modules achieved 100%efficiency,with time resolutions of 75 and 70 ps.Comparatively,the Module 1 works with a lower applied HV at the higher noise level,and time resolution was not influenced greatly by the adhesive tapes and silicones.展开更多
文摘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.
基金Supported by the National Natural Science Foundation of China under Grant No.11020101059,10775082,11050110111 and 10979030
文摘Long-strip multi-gap resistive plate chamber(LMRPC) were built with(Module 1) or without(Module 2) adhesive tapes and silicones.Their performances were investigated by working gas mixtures of different gradient contents(Test 1:94%freon,5%iso-butane and 1%SF_6;Test 2:90%freon,5%iso-butane and 5%SF_6).Both the modules achieved 100%efficiency,with time resolutions of 75 and 70 ps.Comparatively,the Module 1 works with a lower applied HV at the higher noise level,and time resolution was not influenced greatly by the adhesive tapes and silicones.
