Structure and evolution of electron “zebra stripes” in the inner radiation belt
Structure and evolution of electron “zebra stripes” in the inner radiation belt
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内辐射带电子“斑马纹”的结构与演化
DOI：
10.1002/2015ja022077
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
R. Rankin
中科院分区：
文献类型：
--
作者：
Y. Liu;Q. Zong;X.‐Z. Zhou;J. Foster;R. Rankin
“斑马条纹”是内辐射带中新发现的能量在几十到几百keV之间的高能电子能量空间（L壳）分布结构。利用双范艾伦探测器上的辐射带风暴探测器离子组成实验（RBSPICE）的高质量电子通量测量，我们从2013年4月到2014年4月进行了案例和统计研究，研究了L = 3以下斑马条纹的结构和演化特征。结果表明，在电子漂移频率坐标中，斑马条纹可以被转换成均匀间隔的图案；每个L壳区的去趋势对数通量可以用漂移频率的正弦函数很好地描述。这个正弦函数的“波数”对应于漂移频率坐标中两个相邻峰值之间的间隙的倒数，与实时成比例地增加。此外，斑马条纹的这些结构和进化特征可以通过单一单色或静态方位电场下粒子分布演化的解析模型来再现。结果表明，粒子的周期性漂移是形成多重斑马条纹的重要因素。斑马线的振幅与Kp指数呈良好的正相关，表明斑马线的形成机制可能与地磁活动有关。
“Zebra stripes” are newly found energetic electron energy‐spatial (L shell) distributed structure with an energy between tens to a few hundreds keV in the inner radiation belt. Using high‐quality measurements of electron fluxes from Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on board the twin Van Allen Probes, we carry out case and statistical studies from April 2013 to April 2014 to study the structural and evolutionary characteristics of zebra stripes below L = 3. It is revealed that the zebra stripes can be transformed into evenly spaced patterns in the electron drift frequency coordinate: the detrended logarithmic fluxes in each L shell region can be well described by sinusoidal functions of drift frequency. The “wave number” of this sinusoidal function, which corresponds to the reciprocal of the gap between two adjacent peaks in the drift frequency coordinate, increases in proportion to real time. Further, these structural and evolutionary characteristics of zebra stripes can be reproduced by an analytic model of the evolution of the particle distribution under a single monochromatic or static azimuthal electric field. It is shown that the essential ingredient for the formation of multiple zebra stripes is the periodic drift of particles. The amplitude of the zebra stripes shows a good positive correlation with Kp index, which indicates that the generation mechanism of zebra stripes should be related to geomagnetic activities.