摘要
针对圆柱腔IEMP振荡问题,通过理论推导给出了空间电荷层振荡频率的量级范围,并利用MCNP程序计算电子发射参数,使用3维PIC程序UNIPIC模拟计算了2种不同尺寸的圆柱腔模型的IEMP波形和粒子分布。结果表明,只有当IEMP的频率与腔模频率在量级上相匹配,且满足空间电荷层振荡频率大于腔基模频率的条件时,才会在腔内形成有效的电磁振荡。在电子发射过程中,出射粒子数及径向电场强度的极大值主要分布于腔内发射面附近。在电子发射结束后,若存在较强的场束相互作用,粒子会在腔内逐渐均匀分布,径向电场沿柱高的分布则为关于柱体中心点的对称分布;若电子初速度较大,场束作用不明显,则场与粒子会迅速消失。
The electromagnetic resonance of internal electromagnetic pulse(IEMP)in a cylindrical cavity is modeled by using 3-D particle-in-cell(PIC)code UNIPIC,and the electron emission parameters are calculated by using MCNP program.Analytical calculation is deduced to give the order of the frequency of the space charge boundary.Two cylindrical cavity models with different size are computed,and then the condition of resonance is given.It is figured out that the valid electromagnetic resonance occurs in the cavity only when the frequency of IEMP matches the frequency order of cavity mode and meets the condition that the oscillation frequency of space charge layer boundary is larger than the eigenfrequency of the fundamental mode of the cavity.Moreover,the simulation indicates that the maximum electron density and radial electric field located near the emitting surface during the electron emission,while the distribution of radial electrical field becomes symmetry with respect to the midpoint of axis,and the distribution of electrons in the cavity becomes uniform after the electron emission owing to the interaction between fields and particles,or the fields and particles will disappear quickly in the situation that the initial velocity of emission electron is fast result in ignorable interaction between fields and particles.
作者
陈剑楠
任泽平
乔海亮
CHEN Jian-nan;REN Ze-ping;QIAO Hai-liang(Northwest Institute of Nuclear Technology,Xi’an 710024,China)
出处
《现代应用物理》
2020年第2期6-14,共9页
Modern Applied Physics
基金
强脉冲辐射环境模拟与效应国家重点实验室专项经费资助项目(SKLIPR1601Z)。
