| 一次磁层亚暴期间磁场偶极化的尾向传播 |
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| 引用本文： | 曹馨,濮祖荫,张辉,傅绥燕,马志伟,肖池阶,刘振兴,谢伦,Dunlpo M. W.,Korth A.,Frazen M.,Zong Q. G.,Lueck E.,Carr C.,Reme H..一次磁层亚暴期间磁场偶极化的尾向传播[J].地球物理学报,2007,50(4):995-1004. |
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| 作者姓名： | 曹馨 濮祖荫 张辉 傅绥燕 马志伟 肖池阶 刘振兴 谢伦 Dunlpo M. W. Korth A. Frazen M. Zong Q. G. Lueck E. Carr C. Reme H. |
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| 作者单位： | 1.北京大学地球与空间科学学院，北京 100871 2 中国科学院空间科学与应用研究中心，北京 100080 3 中国科学院等离子体物理研究所，合肥 230026 4 中国科学院国家天文台，北京 100012 5 Space Science and Technology Department, Rutherford Appleton Laboratory, UK 6 Max_Planck_Institute for Solar System Research, Germany；7 CSP, Boston |
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| 基金项目： | 国家基金委重大课题“地球空间暴多时空尺度物理过程研究”（40390150）和重点课题“磁层亚暴触发过程的全球MHD-Hall数值模拟”（40536030）支持,属于北京市重点学科支持项目.致谢感谢中国双星-Cluster数据中心的大力支持,感谢WDC数据中心提供地面磁场数据,感谢UCLA空间数据中心提供的Polar磁场数据;感谢Berkeley大学的Mende提供极光数据. |
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| 摘 要： | 利用TC1、Cluster和Polar结合极光和同步高度及地磁的观测，研究了2004年9月14日1730～1930 UT时间段的亚暴偶极化过程.此前行星际磁场持续南向几个小时.亚暴初发(Onset)开始于1823 UT.2 min之后，同步高度的LANL 02A在子夜附近观测到了明显的能量电子增强（Injection）事件，而TC1在1827UT左右在磁尾(-10,-2, 0)RE (GSE)观测到了磁场BX的突然下降，伴随着等离子体压强和温度的突然增加及磁场的强烈扰动.在(-16, 1, 3)RE (GSE) 的Cluster上相同的仪器观测到相同的现象，只是比TC1观测到的晚大约23 min，在1850 UT左右.虽然Polar在更靠近地球的较高纬度(-75, 35, -40)RE (GSE)附近，也在1855 UT左右观测到了这种磁场偶极化现象.以上的观测时序表明TC1、Cluster观测到的磁场偶极化比亚暴偶极化初始发生分别晚4 min和27 min.说明偶极化由近磁尾向中磁尾传播.详细计算表明偶极化源区的位置大约在X=-77RE～-86RE，而传播速度大约为70 km·s-1.在这个事件中亚暴的物理图像可能是中磁尾的近地重联产生的地向高速流到达近磁尾，为近磁尾的亚暴触发创造了条件；亚暴在近磁尾触发之后，磁场偶极化峰面向中磁尾传播.
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| 关 键 词： | 国家基金委重大课题“地球空间暴多时空尺度物理过程研究”（40390150）和重点课题“磁层亚暴触发过程的全球MHD Hall数值模拟”(40536030)支持 属于北京市重点学科支持项目. |
| 文章编号： | 0001-5733（2007）04-0995-10 |
| 收稿时间： | 2006-5-25 |
| 修稿时间： | 2006-05-252007-04-27 |
Dipolarization observed by TC1 and ClusterII during substorm in Sep. 14, 2004 |
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| CAO Xin,PU Zu-Yin,ZHANG Hui,FU Sui-Yan,MA Zhi-Wei,XIAO Chi-Jie,LIU Zhen-Xing,XIE Lun,Dunlpo M. W.,Korth A.,Frazen M.,Zong Q. G.,Lueck E.,Carr C.,Reme H.,Glassmeier K. H..Dipolarization observed by TC1 and ClusterII during substorm in Sep. 14, 2004[J].Chinese Journal of Geophysics,2007,50(4):995-1004. |
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| Authors: | CAO Xin PU Zu-Yin ZHANG Hui FU Sui-Yan MA Zhi-Wei XIAO Chi-Jie LIU Zhen-Xing XIE Lun Dunlpo M W Korth A Frazen M Zong Q G Lueck E Carr C Reme H Glassmeier K H |
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| Institution: | 1.School of Earth and Space Science, Peking University, Beijing 100871, China 2 Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, China 3 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230026, China |
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| Abstract: | We study the substorm dipolarization occurring from 1730 to 1930 UT on Sep.14, 2004 based on DSP/TC1, Cluster and Polar data, combined with the aurora and geosynchronous energetic particle measurements and ground based magnetic field observations. During this time period the IMF was continuously southward. Substorm onset started at about 1823 UT. Two minute later, energetic electron injection was observed by LANL 02A in the pre midnight sector at geostationary orbit. At～1827 UT TC1, which was located at (-10,-2, 0) RE (GSE) in the near Earth tail, saw a sharp decrease of magnetic BX component, accompanied by sudden increases in both the ion temperature and thermal pressure. About 23 minutes later at ～1850 UT, the same signatures as observed by TC1 were observed by Cluster at (-16, 1, 3)RE (GSE) in the mid tail. Meanwhile, Polar, which was located much higher and more close to the Earth at (-75, 35, -40)RE (GSE), saw a sudden change in the elevation of the magnetic field at about 1855 UT. Aforementioned time sequence of substorm activities indicates that the expansion onset took place at about 1823 UT and TC1 and Cluster observed dipolarization (tail expansion) 4 and 27 minutes later, respectively. This means that tail expansion was propagated from source region in the near Earth tail to the mid tail. Detailed calculations imply that the source of the dipolarization was situated at X=-77RE to -86RE and the propagation speed was about 70 km·s-1 A substorm paradigm is proposed to explain the observations in this substorm event: Earthward flow produced by lobe reconnection in the mid tail creates favorable conditions for substorm initiation in the near Earth; after the expansion onset the dipolarization front propagates down to the tail. |
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| Keywords: | Dipolarization Substorm Near Earth reconnection Continues lobe reconnection Pi2 |
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