二次电子发射对系统电磁脉冲的影响  

Effect of secondary electrons on SGEMP response

作　　者：张含天 周前红[1] 周海京[1] 孙强 宋萌萌 董烨[1] 杨薇[1] 姚建生 Zhang Han-Tian;Zhou Qian-Hong;Zhou Hai-Jing;Sun Qiang;Song Meng-Meng;Dong Ye;Yang Wei;Yao Jian-Sheng(Institute Applied Physics and Computational Mathematics,Beijing 100094,China)

机构地区：[1]北京应用物理与计算数学研究所,北京100094

出　　处：《物理学报》2021年第16期182-190,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12005023)资助的课题。

摘　　要：系统电磁脉冲难以有效屏蔽,会显著影响低轨航天器等重要装置和基础设施的性能.为了评估二次电子对系统电磁脉冲的影响,本文基于粒子云网格方法,建立了三维非稳态系统电磁脉冲模型,计算并比较了不同电流密度、金属材料等条件下,两种典型结构的电磁脉冲响应.结果表明,在计算模型中忽略二次电子发射会使部分位置的峰值电场强度被低估2—3倍,电场响应持续的时间也会被低估10%以上.在各类二次电子中,背散射电子对系统电磁脉冲的影响占主导,而真二次电子的作用约为背散射电子的1/5.二次电子发射对系统电磁脉冲的影响随着系统所用材料原子序数的增高而加大.空间电荷效应较强时,二次电子才会对腔体外系统电磁脉冲产生影响.本研究有助于更好地通过数值模拟来获得具体装置在强辐射环境下的系统电磁脉冲响应.It is difficult to effectively shield the system generated electromagnetic pulse(SGEMP),which can significantly affect the performance of important electronic devices and infrastructure,such as low-orbit spacecraft.Numerical simulation is an essential way to study the SGEMP response.However,many previous studies ignored or simplified the effect of secondary electron emission in their models.In this paper,a threedimensional electromagnetic particle-in-cell numerical simulation model is developed to evaluate the effect of secondary electrons on the SGEMP response of two typical structures(external SGEMP and cavity SGEMP,respectively)under different current densities(0.1-100 A/cm2)and different materials(Al,Cu and Au).A right cylinder or cylindrical cavity with a length of 100 mm is used.The photoelectrons produced by the interaction between the X-ray photon and metal are emitted from one end of the system and assumed to be monoenergetic.The photoelectron pulse follows a sine-squared distribution,and its full width at half maximum is 1 ns.Some important parameters of secondary electrons are discussed and summarized,including the emission coefficients of elastically and inelastically backscattered electrons,as well as the probability density functions of emission angles and energies.The results show that ignoring the secondary emission in the simulation model leads the peak electric field to be underestimated by twice-thrice,and the duration of electric field response by more than 10%.The oscillation frequency and the amplitude of the second peak of the tangential magnetic field are also increased,with the secondary electrons considered.Among various types of secondary electrons,backscattered electrons have a dominant effect on the change of SGEMP.The effect of true secondary electrons is about 1/5 of that of backscattered electrons.The effect of secondary electrons on SGEMP response increases with a higher atomic number of the material used in the system,mainly due to higher backscattering emission coefficient and a

关 键 词：二次电子发射 系统电磁脉冲 光电子 全电磁粒子模拟方法 

分 类 号：O462.2[理学—电子物理学]