风云3C对不同类型辐射带电子分布变化的观测:2015年3月17日磁暴事件分析  

Observations of different populations of radiation belt electrons by FengYun 3C:An analysis of the 17 March 2015 geomagnetic storm event

作　　者：胡立凡 项正 顾旭东[1] 倪彬彬[1] 张效信[3] 郭建广 张贤国 朱昌波 郭德宇 付松[1] 刘阳希子 董俊虎 赵怡雯 HU LiFan;XIANG Zheng;GU XuDong;NI BinBin;ZHANG XiaoXin;GUO JianGuang;ZHANG XianGuo;ZHU ChangBo;GUO DeYu;FU Song;LIU YangXiZi;DONG JunHu;ZHAO YiWen(Department of Space Physics,School of Electronic Information,Wuhan University,Wuhan 430072,China;Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing100029,China;National Center for Space Weather,China Meteorological Administration,Beijing100081,China;National Space Science Center,Chinese Academy of Sciences,Beijing100190,China)

机构地区：[1]武汉大学电子信息学院,武汉430072 [2]中国科学院地质与地球物理研究所,地球与行星物理重点实验室,北京100029 [3]中国气象局国家空间天气监测预警中心,北京100081 [4]中国科学院国家空间科学中心,北京100190

出　　处：《地球物理学报》2023年第6期2252-2262,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42025404,42188101,42174190,42274199,42204160,41974186);中国科学院战略性先导科技专项(B类)(XDB41000000);中国科学院地质与地球物理研究所地球与行星物理重点实验室开放课题(DQXX2021-04);中国博士后科学基金(2019M662700);民用航天预研项目(D020308,D020104,D020303)资助。

摘　　要：风云3C卫星(简称FY-3C)测量的低地球轨道(Low Earth Orbit,简称LEO)高能粒子(电子、质子和重离子)通量,是空间环境监测预警业务的重要自主数据来源.深入分析风云3C卫星测量的不同种类高能电子的分布特征和变化规律,对辐射带研究和空间天气预报具有重要意义.本文使用FY-3C测量的空间粒子数据,系统分析了2015年3月17日强磁暴期间辐射带捕获、准捕获和沉降电子的演化特征及其主导性物理机制.结果表明,在磁暴主相,外辐射带电子通量(E2:0.35~0.65 MeV,E3:0.65~1.2 MeV)出现快速下降,达到两个数量级,E1能级(E1:0.15~0.35MeV)电子通量在L<5区域因为亚暴注入先出现增长,之后在L>4的区域出现明显下降.在磁暴恢复相,由于合声波(chorus waves)先加速低能段电子,E1能段电子通量最先(小于五小时)开始增加,在磁暴结束时覆盖2<L<8范围,通量最高达到105 cm^(-2)·sr^(-1)·s^(-1).电子能段越高通量增长得越慢(E2:十小时内;E3:一天内),最终覆盖的空间范围更小(E2:2<L<7;E3:2.5<L<6.5).通过对比沉降电子、准捕获电子和捕获电子通量演化过程的差异性,发现磁暴主相捕获电子通量(E1,E2,E3能段)大幅下降时沉降电子通量并未明显增加,表明此时高能电子(E1,E2,E3能段)的损失机制主要是穿过磁层顶损失,而不是沿着磁力线沉降到中性大气.三种类型的电子通量在磁暴恢复相均出现明显增强,而合声波对电子同时存在加速和散射作用,因此判断恢复相电子的加速机制主要是合声波与电子的回旋共振作用.这些结果表明强磁暴期间辐射带电子呈现出复杂多变的动力学演化特征,风云3C测量的低轨道粒子数据可以为分析辐射带中粒子损失和加速过程中主导的物理机制提供关键信息,是空间辐射环境建模和预测预报的有力支撑.The energetic particle(electrons,protons and heavy ions)fluxes measured by FengYun 3C satellite at the Low Earth Orbit provide a crucial independent data source for space environment monitoring.It is of great importance to comprehensively investigate variation features of distinct populations of energetic electrons for radiation belt research and space weather forecasting.In this study,using the particle flux data measured by FengYun 3C,the evolution features and dominant physical mechanisms of trapped,quasi-trapped,and untrapped energetic electrons during the 17 Marth 2015storm are investigated systematically.The results show that in the main phase of the geomagnetic storm,outer radiation belt electron fluxes(E2:0.35~0.65MeV,E3:0.65~1.2 MeV)promptly decreased two orders of magnitude and electron fluxes at E1 channel(E1:0.15~0.35 MeV)increased firstly at L<5due to substorm injections and then reduced obviously at L>4.In the recovery phase,electron fluxes at E1channel recovered first(within five hours),covered 2<L<8spatial range,reaching 105 cm^(-2)·sr^(-1)·s^(-1) flux level at the end of this storm due to electron accelerations driven by chorus waves.Regarding the higher energy channel,electron fluxes increased later(E2:within ten hours;E3:within one day)and covered narrow spatial range(E2:2<L<7;E3:2.5<L<6.5).Based on the distinct variation features of precipitation,quasi-trapped,and trapped electrons,we found that untrapped electron fluxes do not increase when trapped electron(E1,E2,E3channel)fluxes decrease significantly during the main phase of the 17 March 2015storm,indicating that the main loss mechanism of energetic electrons(E1,E2,E3channel)is magnetopause shadowing rather than loss into the atmosphere.Chorus waves are mainly responsible for the electron flux enhancements during the recovery phase,since the fluxes of three type electrons enhanced significantly in the recovery phase and chorus waves produce both acceleration and scattering effects on electrons.These results indicate that electrons in the

关 键 词：风云3C卫星 磁暴 捕获电子 准捕获电子 沉降电子 

分 类 号：P353[天文地球—空间物理学]