用MCP方程求解雷电分支通道辐射电磁场  

Solving Radiated EM Field of Lightning Branch Channel by MCP Equation

作　　者：刘舟 张云峰[1] 赵晨龙 LIU Zhou;ZHANG Yun-feng;ZHAO Chen-long(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME),Nanjing University of Information Science&Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室,南京210044

出　　处：《微波学报》2022年第6期78-83,共6页Journal of Microwaves

摘　　要：在雷电科学研究和雷电防护技术开发中,闪电通道电磁场辐射特性建模一直是人们关注的重点。人们常采用理想垂直通道进行建模,用各种解析和数值方法得到较为有效的结果,而研究带分支通道等精细通道结构的则较少,因而垂直模型得到的场可能和实际测得场有一定偏差。文中基于运动带电粒子(MCP)方程计算了雷电分支通道的回击电磁场,分别计算了辐射场、速度场与静电场分量以及总场。结果发现分支通道的存在导致了次峰值的出现,波形与观测点位置、回击速度、分叉点高度等参数有关,运动带电粒子速度矢量的改变正好契合这一特点,更能体现回击过程中的物理特性。相比于偶极子求解方法,该方法避免了回击电流的微分运算,是一种高效分析雷电通道辐射场的方法。The modeling of electromagnetic field radiation characteristics of lightning channel has always been a key issue in the lightning protection technology development and lightning science research.Ideal and simple vertical channels are often used for modeling,various analytical and numerical methods are adopted to get more effective results.However,there are few researches on fine channel structures such as branched channels,so the fields obtained by vertical models may deviate from the actual measured fields.In this paper,based on the equation of moving charged particles(MCP),the return electromagnetic field of lightning branch channel is calculated,and the components of radiation field,velocity field and electrostatic field and the total field are calculated respectively.The results show that the existence of branch channel leads to the appearance of subpeak,and the waveform is related to the observation point position,the speed of return stroke,the height of bifurcation point and other parameters.The change of velocity vector of MCP is just in line with this characteristic and can better reflect the physical characteristics in the process of return stroke.Compared with dipole solution method,this method avoids the differential operation of return current,and is an efficient method to analyze the radiation field of lightning channel.

关 键 词：运动带电粒子 回击模型 闪电电磁场 辐射特性 

分 类 号：P427.3[天文地球—大气科学及气象学]