H^(+)频段EMIC波对辐射带相对论电子的投掷角扩散系数的多维建模  

Multiple-dimensional modeling of pitch-angle scattering rates induced by H^(+)band EMIC waves on radiation belts relativistic electrons

作　　者：雷良建 马新 顾旭东[1] 项正 曹兴[1] 王敬之 朱琪 倪彬彬[1] LEI LiangJian;MA Xin;GU XuDong;XIANG Zheng;CAO Xing;WANG JingZhi;ZHU Qi;NI BinBin(Department of Space Physics,School of Electronic Information,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学电子信息学院空间物理系,武汉430072

出　　处：《地球物理学报》2022年第7期2378-2393,共16页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42025404,42188101,41904143,41904144);中国科学院先导B计划(XDB41000000);民用航天预研项目(D020303,D020308,D020103)资助。

摘　　要：电磁离子回旋波(Electromagnetic ion cyclotron waves,简称EMIC波)在地球辐射带电子动力学过程中扮演着非常重要的角色.通过波粒相互作用,EMIC波能有效地散射相对论电子,造成辐射带相对论电子快速沉降损失从而影响相对论电子通量演化.因此在地球辐射带动力学建模中,快速准确地获取EMIC波对相对论电子的散射效应信息非常必要.利用基于准线性理论的Full Diffusion Code(FDC),本文主要研究了辐射带H^(+)频段EMIC波对相对论电子的散射效应,并定量计算了EMIC波对相对论电子的弹跳平均投掷角扩散系数.为了方便快速地进行辐射带多维度建模,我们建立了L=1.5~7,α^(*)=3~30范围内的扩散系数矩阵库.文中展示了L分别为3、4和5时α^(*)为3~30时H^(+)频段EMIC波三种不同传播角模型的弹跳平均投掷角扩散系数,其随不同输入参数的变化特征与前人结果基本一致.基于所建立的弹跳平均投掷角扩散系数矩阵库,我们使用线性插值方法计算得到了L为3.25、4.35、5.55时在等离子体层顶内外的弹跳平均投掷角扩散系数.通过计算比较FDC和线性插值两种方法得到的扩散系数的相对误差,我们进一步验证了线性插值方法对于快速获取扩散系数的可行性和准确性.我们的结果表明,扩散系数的多维矩阵构建和线性插值获取能有效提高辐射带动力学建模的效率,对地球辐射带动理学快速建模和空间天气预报有着重要意义.Electromagnetic ion cyclotron waves(EMIC waves)play important roles in the electron dynamics in the Earth′s radiation belts.Through wave-particle interactions,EMIC waves can effectively scatter relativistic electrons,leading to the rapid loss of relativistic electrons.Therefore,it is very important to quantitively evaluate the scattering effect on relativistic electrons induced by EMIC waves for Earth′s radiation belt dynamic modeling.Using the Full Diffusion Code(FDC)based on the quasi-linear theory,this study mainly focuses on estimating the scattering effect of H^(+)band EMIC waves by calculating the bounce-averaged pitch angle diffusion rates.To easily model the Earth′s radiation belts,we establish the diffusion coefficient matrix library with L=1.5~7 andα^(*)=3~30.This study presents the bounce-averaged pitch angle diffusion coefficients with three different propagation models for H^(+)band EMIC waves when L is 3,4,and 5 withα^(*)about 3~30.Our results based on different input parameters are consistent with the results shown in the previous studies.Depending on the developed diffusion coefficient matrix library,we calculate the bounce-averaged pitch angle diffusion coefficients by linear interpolation method for inside and outside the plasmapause at L~3.25,4.35,and 5.55.By comparing the interpolated diffusion rates with those directly obtained from the FDC calculations,we further calculate the relative errors between the results from the two methods to validate the feasibility and accuracy of the linear interpolation method.Our results show that the diffusion coefficient matrix library associated with the linear interpolation method can effectively improve the efficiency of the radiation belt kinetic modeling,which is very helpful to the kinetic modeling and the relevant space weather forecast of the Earth′s radiation belts.

关 键 词：波粒相互作用 辐射带相对论电子 氢频段EMIC波 投掷角扩散系数 线性插值 

分 类 号：P353[天文地球—空间物理学]