STATISTICAL STUDY OF IPDP EVENTS OBSERVED BY THE CARISMA NETWORK OF MAGNETOMETERS
STATISTICAL STUDY OF IPDP EVENTS OBSERVED BY THE CARISMA NETWORK OF MAGNETOMETERS
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DOI：
10.1002/cjg2.20190
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
Zhou Ming-xia;Yuan Zhi-gang;Li Hai-meng;Wang De-dong;YU Xiong-Dong;Wang Zhen-Zhen-Wang-Zhen-Zhen-2076008213;Qiao Zheng
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文献类型：
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作者：
Zhou Ming-xia;Yuan Zhi-gang;Li Hai-meng;Wang De-dong;YU Xiong-Dong;Wang Zhen-Zhen-Wang-Zhen-Zhen-2076008213;Qiao Zheng
在亚暴期间，从磁尾等离子体片注入的高能离子可以在磁层内激发电磁离子回旋波。作为EMIC波的特征，地面磁力仪观测到了衰减周期脉动间隔（IPDP）。利用GOES卫星和加拿大CARISMA磁力仪网的观测资料，分析了IPDP事件与亚暴注入事件的关系。利用2005年4月至2014年5月CARISMA网络MCMU和MSTK地磁台的观测资料，对亚暴期间IPDP事件进行了统计分析，得到了IPDP事件发生率的季节分布和磁地方时分布。MCMU和MSTK台站同时观测到总共128个IPDP事件。冬季发生率最低（13.28%），春季发生率最高（32.81%）。结果表明，IPDP事件的发生率受电离层电导率和亚暴发生率的影响。事件的最大发生率在15 MLT和18 MLT之间。我们的研究结果表明，IPDP事件主要是由高能各向异性质子产生的，这些质子可以在亚暴期间注入内磁层并向西漂移并遇到等离子体层羽流。
During substorms energetic ions injected from the magnetotail plasma sheet could excite electromagnetic ion cyclotron (EMIC) waves in the inner magnetosphere. As a signature of EMIC waves, ground-based magnetometers observed the Intervals of Pulsations of Diminishing Periods (IPDP). With the observations of the GOES satellite and CARISMA network of magnetometers in Canada, we analyzed the relationship between the IPDP events and substorm injection events. With the observations of magnetometers at MCMU and MSTK stations of CARISMA network between April 2005 and May 2014, we statistically analyzed the IPDP events during substorms and obtained the occurrence rate distribution in seasons and magnetic local time (MLT). A total of 128 IPDP events have been simultaneously observed by both MCMU and MSTK stations. The IPDP events have the least occurrence rate in winter (13.28%), and the highest occurrence rate in spring (32.81%). The results show that the occurrence rate of IPDP events is affected by the ionospheric conductivity and the occurrence rate of substorms. The maximum occurrence rate of the events is between 15 MLT and 18 MLT. Our result suggests that IPDP events are mainly generated by energetic anisotropic protons, which can be injected into the inner magnetosphere during substorms and drift westward and encounter the plasmaspheric plume.