大尺度场向电流及其与单色极光电子的联系--Swarm卫星观测  

The relationship between large scale field-aligned current and monoenergetic auroral electron observed by Swarm satellite

作　　者：张琬 蔡红涛[1] 周康俊 张宏 高顺祖 ZHANG Wan;CAI HongTao;ZHOU KangJun;ZHANG Hong;GAO ShunZu(School of Electronic Information,Wuhan 430072,China)

机构地区：[1]武汉大学电子信息学院,武汉430072

出　　处：《地球物理学报》2020年第4期1262-1270,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41574148,41431073)共同资助.

摘　　要：Swarm卫星A/C在480km左右高度伴飞,通过二者磁场观测数据,可在不需假设无限大垂直电流片的情况下更加真实地计算出场向电流(FAC).本文利用最新的Swarm观测数据,研究了大尺度场向电流的时空分布特征,及其对行星际条件的依赖;结合极光沉降粒子时空分布信息,探究了场向电流可能载流子及其源区.分析发现:(1)IMF Bz分量主要控制FAC的强度大小,By分量主要改变FAC的结构与分布,最为明显的是0区FAC;(2)昏侧1区上行FAC与单色极光电子的高发区域具有较高的重合度,且在不同行星际条件下均表现出相类似的纬度分布;(3)在上述区域内,FAC密度与单色极光电子能通量表现出较好的相关性.这表明单色极光电子对昏侧1区上行电流起着重要贡献.Swarm spacecraft A/C are flying side by side at altitude of 480 km.According to the magnetic field observations from the two crafts,the large scale field-aligned currents can be virtually figured out without the assumption of infinite vertical current chip.In this paper large scale FAC measurements derived from Swarm observations are investigated to explore the spatial and temporal distribution of large scale FAC under various interplanetary magnetic field conditions,as well as the current carriers and their possible source regions.Several novel founding includes:(1)IMF Bzcomponent changes the magnitude of FAC,while FAC structure and distribution are mainly controlled by the Bycomponent,especially for R0 current;(2)At dusk,the correlation between R1 upward current and precipitation was especially high,where the monoenergetic auroral electron is dominated;(3)In the aforementioned area,the density of R1 FAC and monoenergetic electron flux exhibited close linear correlation,suggesting the important contribution of the monoenergetic auroral electron to R1 current at dusk.

关 键 词：场向电流 行星际磁场 单色电子极光 

分 类 号：P352[天文地球—空间物理学]