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Shrinkage of magnetosphere observed by TC-1 satellite during the high-speed solar wind stream

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Science China(Technological Sciences) 2008年第10期51卷 1695-1703页

作者： H. RME I. dANdOURAS C. M. CARR centre d'etude spatiale des rayonnements BP 4346 31028 Toulouse cedex 4 France The Blackett Laboratory Imperial College London SW7 2BZ UK

during the interval 06:14―07:30 UT on August 24, 2005, since the Earth’s magneto- pause was suddenly compressed by the persistent high-speed solar wind stream with the southward component of the interplanetary magnetic field (IMF), the magnetopause moved inward for about 3.1 RE. Meanwhile, TC-1 satellite shifted from northern plasma sheet to the northern lobe/mantle region, although it kept inward flying during the interval 06:00―07:30UT. The shift of TC-1 from the plasma sheet to the lobe/mantle is caused by the simultaneous inward displacements of the plasma sheet and near-Earth lobe/mantle region, and their inward movement velocity is larger than the inward motion velocity of TC-1. The joint inward dis-placements of the magnetopause, the lobe/mantle region and the plasma sheet indicate that the whole magnetosphere shrinks inward due to the magnetospheric compression by the high-speed solar wind stream, and the magnetospheric ions are attached to the magnetic field lines (i.e. ‘frozen’ in magnetic field) and move inward in the shrinking process of magnetosphere. The large shrinkage of magne-tosphere indicates that the near-Earth magnetotail compression caused by the strong solar wind dynamic pressure is much larger than its thickening caused by the southward component of the IMF, and the locations of magnetospheric regions with different plasmas vary remarkably with the variation of the solar wind dynamic pressure.

关键词： solar wind dynamic pressure shrinkage of magnetosphere storm sudden commencement substorm

Statistical research on the motion properties of the magnetotail current sheet:Cluster observations

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Science China(Technological Sciences) 2010年第6期53卷 1732-1738页

作者： H.REME E.LUCEK centre d'etude spatiale des rayonnements University Paul SabatierUniversity of ToulouseToulouseFrance UMR 5187 CNRSToulouseFrance Space and Atmospheric Physics Group Blackett LaboratoryImperialCollegeLondonUK

The origin of the flapping motion of the earth’s magnetotail current sheet is one of the most important problems in the magnetotail *** Cluster data,we make a statistical research on the motion properties of the magnetotail current sheet of 2001 and *** calculate the velocities of the magnetotail current sheet using new methods and obtain the distribution of the magnetotail current sheet velocities in the X-Y plane in GSE coordinate *** results show that although most of the current sheets were propagating toward the tail flanks and those of the exceptions lay in dusk side,which is consistent with previous studies,the proportions of the current sheet which were propagating toward midnight (where |YGSE|=0) were higher than those in previous *** of the current sheet in the middle area (|YGSE|ddle area of the magnetotail might be a source region for the motion of the current sheets which were propagating towards the tail *** to our case studies,the way the current sheets propagated toward midnight area differs significantly from that toward dusk and dawn side,from which we infer that there might be two different kinds of current sheet motions originated from different *** statistical results of this paper may give some clues for further studies on the origin of the flapping motion of the magnetotail current sheet.

关键词： magnetotail current sheet flapping motion source

Near-Earth bursty bulk flows and AE index

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Science China(Technological Sciences) 2008年第10期51卷 1704-1712页

作者： W BAUMJOHANN M. W. dUNLOP C. CARR H. RME Space Research Institute Austrian Academy of Sciences Graz Austria Space Sciences division Rutherford Appleton Laboratory Chilton Didcot UK Imperial College London United Kingdom centre d'etude spatiale des rayonnements Toulouse France

With the 4-s resolution data of the magnetometer and the ion plasma analyzer on TC-1 from June to November of each year during the period of 2004―2006, we statistically analyzed the occurrence rate of both convective and field-aligned bursty flows (FABFs). A near-Earth bursty bulk flow (NEBBF) occurred during both the quiet time and substorm process. In general, the magnetic field and the plasma density began oscillating with the appearance of the NEBBF associated with a distinct increase of the AE index. The increase of AE index during the NEBBF was more than 100 nT in both quiet time and substorm process. The statistical analysis indicated that the occurrence rates of the FABFs were nearly the same in the dif-ferent stages of the AE index, but the occurrence rate of the NEBBFs was much higher in the growth stage of the AE index, indicating that the NEBBFs were di-rectly related to the growth and expansion phases of the substorm. The observa-tions suggested that the quite large number of BBFs from the mid magnetotail could enter into the near-Earth tail and play important role in triggering the sub-storm onset.

关键词： BBF near-Earth AE index substorm onset

磁宁静期磁尾爆发性整体流持续时间多点卫星研究

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地球物理学报 2005年第2期48卷 252-258页

作者：马玉端曹晋滨周国成刘振兴 H.Reme I.dandouras 中国科学院空间科学与应用研究中心 centre d'etude spatiale des rayonnements 31028 Toulouse France

本文利用星簇CLUSTER的三颗卫星数据分析了磁宁静期磁尾爆发性整体流(BBFs,BurstyBulkFlows)的时间尺度,并与单个卫星的结果做了比较.事例研究表明,利用三颗卫星观测数据判断的BBFs的时间尺度比单个卫星的大一倍左右.对于三颗卫星观测... 详细信息

本文利用星簇CLUSTER的三颗卫星数据分析了磁宁静期磁尾爆发性整体流(BBFs,BurstyBulkFlows)的时间尺度,并与单个卫星的结果做了比较.事例研究表明,利用三颗卫星观测数据判断的BBFs的时间尺度比单个卫星的大一倍左右.对于三颗卫星观测到的同一个BBFs ,BBFs在晨昏方向上的摆动决定了CLUSTER的三个卫星观测到BBFs的先后次序.三颗卫星的观测也显示了BBFs的高度局域化特征.磁宁静期磁尾BBFs寿命的增大,使得BBFs携带的质量和能量的地向输运增加.这种地向输运增加的结果是:磁尾储存的能量得到较为平稳的释放,改变了亚暴起始产生的时间,为解决磁层压力平衡矛盾(PBI,PressureBalanceInconsistency)问题提供了新的思路.

关键词： BBFs 局域化输运摆动时间尺度

A Theoretic Interpretation of Movement of the Cusp Equatorward Boundary

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空间科学学报 2005年第5期25卷 412-418页

作者： J. B. Cao A. Leonovich G. C. Zhou Z. X. Liu H. Reme I. dandouras Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China China-Russia Joint Research Center on Space Weather Beijing 100080 China centre d＇etude spatiale des rayonnements 31028 Toulouse France

A preliminary model is proposed to describe quantitatively the position and movement of cusp equatorward boundary. This integrated model, consisting of an empirical model of the magnetopause and a compressed dipolar model of Open/Closed field line, connects quantitatively the solar wind conditions, subsolar magnetopause and cusp equatorward boundary. It is shown that the increasing solar wind dynamic pressure and the increasing southward Interplanetary Magnetic Field (IMF) component drive the magnetopause to move inward and the cusp equatorward. This model is adopted to interpret quantitatively the cusp movement of August 14, 2001 observed by Cluster. The results show that the subsolar magnetopause moved earthward from 10.7 Re to 9.0Re during the period of 002300-002800 UT, and correspondingly the cusp equatorward boundary shifted equatorward. The observations of Cluster C1 and C4 show the cusp equatorward boundary that Cluster C1 and C4 were crossing during same interval moved equatorward by 4.6°. The cusp equatorward boundary velocity computed in the theoretical model (10.7 km/s) is in good agreement with the observed value(9.4km/s) calculated from the data of CIS of Cluster C4 and C1.

关键词：太阳风赤道边界线磁场

Multi-spacecraft observations of earthward flow bursts

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Science China(Technological Sciences) 2012年第5期55卷 1305-1311页

作者： MA Yuduan CAO JinBin REME Henry dANdOURAS Iannis dUNLOP Malcolm LUCEK Elisabeth School of Astronautics Beihang UniversityBeijing 100191China SOA Key Laboratory for Polar Science Polar Research Institute of ChinaShanghai 200136China centre d'etude spatiale des rayonnements Toulouse 31028France RutherforAppleton Laboratory OxfordshireUK Blackett Laboratory Imperial College LondonLondon SW72AZUK

On the basis of the plasma, electric and magnetic fields jointly observed by Cluster and the double Star TC-I spacecraft in the Earth＇s magnetotail, we have investigated the earthward flow bursts by introducing the momentum equation in the X-direction in the ideal conditions of magneto hydrodynamics （MHd）. One earthward flow burst with a peak in excess of 500 km/s was selected, when the four spacecraft of Cluster were located around -16 RE and TC-1 was located around -10 RE in the X-direction. The inter-spacecraft distances in Y and Z directions were smaller than the statistical spatial scales of the bursty bulk flows. When the Y components of E and -VxB were compared, there was no clear breakdown of the frozen-in condition during the earthward flow burst. With the measured plasma and magnetic parameters from two spacecraft at different positions in the magnetotail, the X component of the pressure gradient was calculated. Magnetic tension was calculated using the mag- netic field measured at four points, which could be compared with the assumed constant in the past research with single satel- lite. When the pressure gradient and the magnetic tension were put into the MHd momentum equation, some samples of the earthward flow bursts were accelerated and some were decelerated. The braking process of the earthward flow burst was more complicated than what the past results had shown. The accelerated samples accounted for about one third of the whole earth- ward flow bursts and discontinuously located among the decelerated elements. The original single earthward flow burst event might be split into several short flow bursts when it was moving to the Earth. Our results may partly illustrate that the duration of fast flows during three phases of substorm becomes short near the Earth. The results are consistent with the past results that fast flows intrude to places earthward the typical braking region.

关键词： flow burst pressure gradient magnetic tension braking

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磁层快速对流事件的多点卫星联合观测

地球物理学报 2007年第5期50卷 1277-1282页

作者：马玉端曹晋滨周国成刘振兴 H. Reme I. dandouras E. Lucek 中国科学院空间天气学重点实验室北京100080 centre d'etude spatiale des rayonnements Imperial College London

本文利用星簇Cluster的三颗卫星(C1,C3和C4)在2001年和2002年的数据,研究了快速对流事件(RCE,Rapid Convection Event)及其与亚暴的关系.结果显示单点卫星对RCE的观测,不能反映磁尾RCE的真实情况.在2002年7月25日发生的一次RCE事件,C1... 详细信息

本文利用星簇Cluster的三颗卫星(C1,C3和C4)在2001年和2002年的数据,研究了快速对流事件(RCE,Rapid Convection Event)及其与亚暴的关系.结果显示单点卫星对RCE的观测,不能反映磁尾RCE的真实情况.在2002年7月25日发生的一次RCE事件,C1和C3观测到这次RCE,C4却没有观测到.在三颗卫星联合观测到的306次RCE中,C1观测到215次,C3观测到266次,C4观测到227次.统计研究表明,单点卫星观测到的RCE的平均时间也不能准确反映磁层内的RCE.由此推论在整个中心等离子体片内,快速对流事件所承担的能量和磁通量的输运量,可能远大于单点卫星观测给出的结果.用速度来定义的磁尾爆发性整体流(BBF,Bursty Bulk Flow)与亚暴的关系,比用磁通量定义的RCE与亚暴的关系要更加紧密.

关键词： RCE 磁通量持续时间输运

ULF Waves Associated with Solar Wind deceleration in the Earth＇s Foreshock

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Chinese Physics Letters 2009年第11期26卷 258-261页

作者：符慧山曹晋滨杨彪 Lucek E Reme H dandouras I State Key Laboratory of Space Weather Center for Space Science and Applied Research Beijing 100190 Graduate University of Chinese Academy of Sciences Beijing 100049 Beijing University of Aeronautics and Astronautics Beijing 100190 Institute of Space Physics and Applied Technology Peking University Beijing 100871 Blackett Laboratory Imperial College Prince Consort Road London SW7 2BZ UK centre d'etude spatiale des rayonnements 31028 Toulouse France

Characteristics of ULF waves associated with the solar wind deceleration in the Earth＇s foreshock on 6-7 April 2003 is studied using the wave telescope technique. In the satellite frame, the ULF waves are the left-handed polarized and quasi anti-parallel propagating mode, with a power peak at about 18.63mHz. The wave vector in the GSE coordinates is estimated to be k = （-4.29, 2.28, 1.21）×10^-4 km^-1, In the solar wind frame, the frequency of waves becomes - 9.39 mHz after the doppler shift correction. The propagation direction of the waves is thus reversed and correspondingly the polarization of the waves becomes right-handed. The above-mentioned characteristics of the ULF waves in the solar wind frame indicate that the ULF waves associated with the solar wind deceleration are the Alfven-whistler waves, which have been frequently reported in both the observations and computer simulations.

关键词： Plasma physics Environmental and Earth science Astrophysics and astroparticles

THEMIS observations of two substorms on February 26,2008

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Science China(Technological Sciences) 2010年第5期53卷 1328-1337页

作者： CHU XiangNing PU ZuYin CAO Xin WANG Jue V.MISHIN V.ANGELOPOULOS LIU Jiang WEI Yong K.H.GLASSMEIER J.MCFAddEN d.LARSON S.MENdE H.FREY C.T.RUSSELL I.MANN d.SIBECK ZONG QiuGang FU SuiYan XIE Lun T.I.SAIFUdINOVA M.V.TOLOCHKO L.A.SAPRONOVA H.REME E.LUCEK School of Earth and Space Sciences Peking UriiversityBeijing 100871China Institute of Solar-Terrestrial Physics Russian Academy of Sciences IGPP UCLA Instiute of Geophysics and Extraterrestrial Physics Technical University of BraunschweigBraunschweig and Max Planck Institute of Solar System Research Space Sciences Laboratory University of California department of Physics University of Alberta Code 674 NASA/GSFC centre d'etude spatiale des rayonnements Blackett Laboratory Imperial College London

Two substorms occurred at ～04:05 and ～04:55 UT on February 26,2008 are studied with the in-situ observations of THEMIS satellites and ground-based aurora and magnetic field *** et *** made a comprehensive study of the 04:55 UT *** showed detailed features of the two substorms with much attention to the first event and to the rela-tionship between mid-tail magnetic reconnection(MR) and substorm *** was found that in the earlier stage of each substorm,a first auroral intensification occurred 2-3 min soon after the start of mid-tail MR,followed by a slow and very lim-ited *** auroral arcs were weak,short-lived,and localized,characterizing all features of a *** re-garded the first auroral brightening as the initial onset of the substorms.A few minutes later,a second stronger auroral intensification appeared,followed by quick and extensive *** was interesting to note that the second brightening and related poleward expansion happened almost simultaneously(within a couple of minutes) with the onset of earthward flow and dipolarization in the near-Earth tail and other phenomenon of the substorm expansion *** thus regarded the second auroral brightening as the major onset of the ***,it was seen that during the growth phase of the two substorms,the polar cap open flux Ψ kept increasing,while it quickly reduced during the substorm expansion and recovery *** variations of Ψ implied that the evolution of the two substorm expansion phases were closely related to MR of tail lobe open field *** of substorm activities revealed that the two events studied were small substorms;while estimate of MR rate indicated that the MR processes in the two substorms were *** aforementioned observations suggested that mid-tail MR initiated the pseudobreakup first;the earthward flow generated by MR transported magnetic flux and energy to the near-Earth tail to cause the formatio

关键词： substorm auroral intensification/brightening auroral expansion dipolarization magnetic reconnection