一次磁层亚暴期间磁场偶极化的尾向传播
Dipolarization observed by TC1 and ClusterII during substorm in Sep. 14, 2004
查看参考文献32篇
|
文摘
|
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)R_E (GSE)观测到了磁场B_X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)R_E (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(-7.5, 3.5, -4.0)R_E (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=-7.7R_E～-8.6R_E,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. |
|
其他语种文摘
|
We study the substorm dipolarization occurring from 1730 to 1930 UT on Sep. 14, 2004 based on DSP/TCI, 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 TCI, which was located at ( - 10, - 2, 0) R_E(GSE) in the near-Earth tail, saw a sharp decrease of magnetic B_x 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 TCI were observed by Cluster al ( - 16, 1, 3)R_E(GSE) in the mid-tail. Meanwhile, Polar, which was located much higher and more close to the Earth at ( -7.5, 3.5,-4.0) R_E (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 TCI 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 = -7.7R_E to -8.6R_E and the propagation speed was about 70 kin'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. |
|
来源
|
地球物理学报
,2007,50(4):995-1004 【核心库】
|
|
关键词
|
偶极化
;
亚暴
;
近地重联
;
持续尾瓣重联
;
Pi2
|
|
地址
|
1.
北京大学地球与空间科学学院, 北京, 100871
2.
中国科学院等离子体物理研究所, 合肥, 230026
3.
中国科学院国家天文台, 北京, 100012
4.
中国科学院空间科学与应用研究中心, 北京, 100080
5.
Space Science and Technology Department, Rutherford Appleton Laboratory, UK
6.
Max-Planck-Institute for Solar System Research, Germany
7.
CSP, Boston University, USA
8.
The Blackett Laboratory, Imperial College London, UK
9.
CNSR, France
10.
CNSR, France, France
11.
IGM, TU Braunschweig, Germany, Germany
|
|
语种
|
中文 |
|
文献类型
|
研究性论文 |
|
ISSN
|
0001-5733 |
|
学科
|
地球物理学 |
|
基金
|
国家自然科学基金
;
国家自然科学基金
;
北京市重点学科项目基金
|
|
文献收藏号
|
CSCD:2839728
|
参考文献 共
32
共2页
|
|
1.
张辉. 尾瓣持续磁重联与磁层亚暴相关性研究.
科学通报,2006,51(4):459-468
|
被引
2
次
|
|
|
|
|
2.
Frank L A. Observations of magnetic field dipolarization during auroral substorm onset.
J Geophys Res,2000,105(7):15897-15912
|
被引
1
次
|
|
|
|
|
3.
Uozumi Teiji. Propagation characteristics of Pi2 magnetic pulsations observed at ground high latitudes.
J Geophys Res,2004,109(A8):203
|
被引
1
次
|
|
|
|
|
4.
Lee Dong-Hun. On the generation mechanism of Pi2 pulsations in the magnetosphere.
Geophys Res Lett,1998,25(5):583-586
|
被引
1
次
|
|
|
|
|
5.
Takahashi Kazue. Longitudinal structure of low-latitude Pi2 pulsations and its dependence on aurora.
J Geophys Res,2004,109(A12):206
|
被引
1
次
|
|
|
|
|
6.
Zaharia Sorin. Particle transport and energization associated with substorms.
J Geophys Res,2000,105(A8):18741-18752
|
被引
2
次
|
|
|
|
|
7.
Dubyagin S V. Evidence of near-Earth breakup location.
Geophys Res Lett,2003,30(6):1282
|
被引
1
次
|
|
|
|
|
8.
Ohtani S. Temporal structure of the fast convective flow in the plasma sheet:comparison between observations and two-fluid simulations.
J Geophys Res,2004,109(A3):210
|
被引
1
次
|
|
|
|
|
9.
Dewhurst J P. Thinning and expansion of the substorm plasma sheet:Cluster PEACE timing analysis.
Ann Geophys,2004,22:4165-4184
|
被引
1
次
|
|
|
|
|
10.
Sergeev V A. Bi-directional electron distributions associated with near-tail flux transport.
Geophys Res Lett,2001,28(19):3813-3816
|
被引
1
次
|
|
|
|
|
11.
Korth A. Magnetic field configuration and field-aligned acceleration of energetic ions during substorm onsets.
Ann Geophys,2001,19:1089-1094
|
被引
1
次
|
|
|
|
|
12.
Angelopoulos V. Statistical characteristics of bursty bulk flow events.
J Geophys Res,1994,99(11):21257-21280
|
被引
27
次
|
|
|
|
|
13.
Borodkova N L. Plasma sheet fast flows and auroral dynamics during substorm:a case study.
Ann Geophys,2002,20:341-347
|
被引
1
次
|
|
|
|
|
14.
Shiokawa K. Decrease in Bz prior to the dipolarization in the near-Earth plasma sheet.
J Geophys Res,2005,110(A9):219
|
被引
1
次
|
|
|
|
|
15.
Cheng Ching-Chang. Spectral power of low-latitude Pi2 pulsations at the 210.magnetic meridian stations and plasmasphericcavity resonances.
Earth Planets Space,2000,52:615-627
|
被引
1
次
|
|
|
|
|
16.
Liou K. Magnetic dipolarization with substorm expansion onset.
J Geophys Res,2002,107(A7):1131
|
被引
3
次
|
|
|
|
|
17.
Jacquey C J. Location and propagation of the magnetotail current disruption during substorm onset:analysis and simulation of an ISEE multi-onset event.
Geophys Res Lett,1991,18:389
|
被引
2
次
|
|
|
|
|
18.
Lui A T Y. Near-Earth dipolarization:evidence for a non-MHD process.
Geophys Res Lett,1999,26(19):2905-2908
|
被引
5
次
|
|
|
|
|
19.
Baumjohann W. Substorm dipolarization and recovery.
J Geophys Res,1999,104(A11):24995-25000
|
被引
13
次
|
|
|
|
|
20.
Nakamura R. Motion of the dipolarization front during a flow burst event observed by Cluster.
Geophys Res Lett,2002,29(20):1942
|
被引
13
次
|
|
|
|
|
了解气象卫星更多信息，请访问