磁层顶通量传输事件的经验重构
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摘要
在地球磁层顶附近观测到的通量传输事件(Flux Transfer Event,FTE)—般被认为是瞬态局域磁重联的产物,是太阳风质量、动量和能量进入地球内磁层的重要通道.重构FTE的磁场结构可促进对其形成、演化过程及其与周围等离子体环境相互作用的理解.Grad-Shafranov重构法和磁通量绳拟合法等传统磁场重构方法适用于满足特定物理条件的磁场结构.基于平面线性插值原理,设计了一种不受具体物理条件限定的二维FTE磁场结构重构法.模型测试以及对THEMIS和Cluster卫星簇分别观测到的两个FTE的实际应用表明,在合适的多卫星位形条件下,该方法能快速有效重构出FTE的磁场空间分布,有助于推测FTE的磁场线位形,理解卫星测量数据的时间变化,以及分析等离子体物理量相对于FTE的磁场空间分布特征.
Flux Transfer Events(FTEs) observed at the Earth's magnetopause are generally believed to be products of transient and patchy magnetic reconnection processes,serving as linkage channels between solar wind and Earth's magnetosphere and therefore playing a crucial role in the exchange of mass,momentum,and energy between these two regions.Magnetic field reconstruction techniques are useful for better understanding FTE's formation and evolution and its interaction with surrounding environment.Traditional techniques such as Grad-Shafranov reconstruction and FTE model fitting methods,however,are confined to specific physical conditions.A new multi-point method applicable to two-dimensional FTEs in various physical condition is devised based on plane linear interpolation.The applications to two FTEs observed by THEMIS and Cluster show that the method can quickly and efficiently reconstruct the spatial distribution of the magnetic field structure,and will help to infer the magnetic field line configurations,understand the temporal variation of measured data and analyze the spatial distribution characteristic of plasma parameters relative to the magnetic field.
Flux Transfer Events(FTEs) observed at the Earth's magnetopause are generally believed to be products of transient and patchy magnetic reconnection processes,serving as linkage channels between solar wind and Earth's magnetosphere and therefore playing a crucial role in the exchange of mass,momentum,and energy between these two regions.Magnetic field reconstruction techniques are useful for better understanding FTE's formation and evolution and its interaction with surrounding environment.Traditional techniques such as Grad-Shafranov reconstruction and FTE model fitting methods,however,are confined to specific physical conditions.A new multi-point method applicable to two-dimensional FTEs in various physical condition is devised based on plane linear interpolation.The applications to two FTEs observed by THEMIS and Cluster show that the method can quickly and efficiently reconstruct the spatial distribution of the magnetic field structure,and will help to infer the magnetic field line configurations,understand the temporal variation of measured data and analyze the spatial distribution characteristic of plasma parameters relative to the magnetic field.
引文
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[2]RUSSELL C T,ELPHIC R C.ISEE observations of flux transfer events at the dayside magnetopause[J].Geophys.Res.Lett.,1979,6(1):33-36
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[18]SHI Q Q,SHEN C,DUNLOP M W,et al.Motion of observed structures calculated from multi-point magnetic field measurements:application to Cluster[J].Geophys.Res.Lett.,2006,33(8):L08109
[19]ZHOU X Z,ZONG Q G,WANG J,et al.Multiple triangulation analysis:application to determine the velocity of 2-D structures[J].Ann.Geophys.,2006,24(11):3173-3177
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[22]HU Qiang,SONNERUP B U O.Reconstruction of magnetic clouds in the solar wind:orientations and configurations[J].J.Geophys.Res.,2002,107(A7):SSH 10-1-SSH10-15
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[24]RONG Z J,WAN W X,SHEN C,et al.Method for inferring the axis orientation of cylindrical magnetic flux ropebased on single-point measurement[J].J.Geophys.Res.,2013,118(1):271-283
[25]SHI Q Q,SHEN C,PU Z Y,et al.Dimensional analysis of observed structures using multipoint magnetic field measurements:application to Cluster[J].Geophys.Res.Lett.,2005,32(12):L12105
[26]ZHOU X Z,ZONG Q G,PU Z Y,et al.Multiple triangulation analysis:another approach to determine the orientation of magnetic flux ropes[J].Ann.Geophys.,2006,24(6):1759-1765
[27]SHEN C,LI X,DUNLOP M,et al.Magnetic field rotation analysis and the applications[J].J.Geophys.Res.,2007,112(A6):A06211
[28]LI Zhaoyu,CHEN Tao,YAN Guangqing.New method for determining central axial orientation of flux rope embedded within current sheet using multipoint measurements[J].Sci.China Earth Sci.,2016,59(10):2037-2052
[29]FEAR R C,MILAN S E,FAZAKERLEY A N,et al.Motion of flux transfer events:a test of the Cooling model[J].Ann.Geophys.,2007,25(7):1669-1690
[30]SISCOE G L,DAVIS JR L,COLEMAN JR P J,et al.Power spectra and discontinuities of the interplanetary magnetic field:mariner 4[J].J.Geophys.Res.,1968,73(1):61-82
[31]WATSON D F.Contouring:A Guide to the Analysis and Display of Spatial Data[M].New York:Pergamon Press,1992
[32]HASEGAWA H,SONNERUP B U O,OWEN C J,et al.The structure of flux transfer events recovered from Cluster data[J].Ann.Geophys.,2006,24(2):603-618
[33]LUI A T Y.Grad-Shafranov reconstruction of magnetic flux ropes in the near-Earth space[J].Space Sci.Rev.,2011,158(1):43-68
[34]MCFADDEN J P,CARLSON C W,LARSON D,et al.The THEMIS ESA plasma instrument and in-flight calibration[J].Space Sci.Rev.,2008,141(1-4):277-302
[35]AUSTER H U,GLASSMEIER K H,MAGNES W,et al.The THEMIS fluxgate magnetometer[J].Space Sci.Rev.,2008,141(1-4):235-264
[36]DING D Q,LEE L C,MA Z W.Different FTE signatures generated by the bursty single X line reconnection and the multiple X line reconnection at the dayside magnetopause[J].J.Geophys.Res.,1991,96(A1):57-66
[37]REME H,BOSQUED J M,SAUVAUD J A,et al.The Cluster Ion Spectrometry(CIS)experiment[J].Space Sci.Rev.,1997,79(1/2):303-350
[38]BALOGH A,DUNLOP M W,COWLEY S W H,et al.The Cluster magnetic field investigation[J].Space Sci.Rev.,1997,79(1/2):65-91
[39]ESCOUBET C P,SCHMIDT R,GOLDSTEIN M L.Cluster-science and mission overview[J].Space Sci.Rev.,1997,79(1/2):11-32
[2]RUSSELL C T,ELPHIC R C.ISEE observations of flux transfer events at the dayside magnetopause[J].Geophys.Res.Lett.,1979,6(1):33-36
[3]LEE L C,FU Z F.A theory of magnetic flux transfer at the Earth's magnetopause[J].Geophys.Res.Lett.,1985,12(2):105-108
[4]SCHOLER M.Magnetic flux transfer at the magnetopause based on single X line bursty reconnection[J].Geophys.Res.Lett.,1988,15(4):291-294
[5]SONNERUP B U(O|¨),HASEGAWA H,TEH W L,et al.Grad-Shafranov reconstruction:an overview[J].J.Geophys.Res.,2006,111(A9):A09204
[6]HAU L N,SONNERUP B U(O|¨).Two-dimensional coherent structures in the magnetopause:recovery of static equilibria from single-spacecraft data[J].J.Geophys.Res.,1999,104(A4):6899-6917
[7]SONNERUP B U(O|¨),HASEGAWA H.Reconstruction of steady,three-dimensional,magnetohydrostatic field and plasma structures in space:theory and benchmarking[J].J.Geophys.Res.,2011,116(A9):A09230
[8]SONNERUP B U(O|¨),HASEGAWA H,PASCHMANN G.Anatomy of a flux transfer event seen by Cluster[J].Geophys.Res.Lett.,2004,31(11):L11803
[9]HU Qiang,SONNERUP B U(O|¨).Reconstruction of twodimensional structures in the magnetopause:method improvements[J].J.Geophys.Res.,2003,108(A1):SMP9-1-SMP 9-9
[10]BURLAGA L F.Magnetic clouds and force-free fields withconstant alpha[J].J.Geophys.Res.,1988,93(A7):7217-7224
[11]LEPPING R P,JONES J A,BURLAGA L F.Magnetic field structure of interplanetary magnetic clouds at 1AU[J].J.Geophys.Res.,1990,95(A8):11957-11965
[12]KIVELSON M G,KHURANA K K.Models of flux ropes embedded in a Harris neutral sheet:force-free solutions in low and high beta plasmas[J].J.Geophys.Res.,1995,100(A12):23637-23645
[13]ZHANG H,KHURANA K K,KIVELSON M G,et al.Modeling a force-free flux transfer event probed by multiple Time History of Events and Macroscale Interactions during Substorms(THEMIS)spacecraft[J].J.Geophys.Res.,2008,113(A1):A00C05
[14]DE KEYSER J,ROTH M.Structural analysis of periodic surface waves on the magnetospheric boundary[J].Planet Space Sci.,2003,51(12):757-768
[15]SONG P,LE G,RUSSELL C T.Observational differences between flux-transfer events and surface-waves at the magnetopause[J].J.Geophys.Res.,1994,99(A2):2309-2320
[16]PASCHMANN G,DALY P W.Analysis Methods for Multi-Spacecraft Data[M].Noordwijk:Eur.Space Agency,1998:221-248
[17]SONNER.UP B U(O|¨),HASEGAWA H.Orientation and motion of two-dimensional structures in a space plasma[J].J.Geophys.Res.,2005,110(A6):A06208
[18]SHI Q Q,SHEN C,DUNLOP M W,et al.Motion of observed structures calculated from multi-point magnetic field measurements:application to Cluster[J].Geophys.Res.Lett.,2006,33(8):L08109
[19]ZHOU X Z,ZONG Q G,WANG J,et al.Multiple triangulation analysis:application to determine the velocity of 2-D structures[J].Ann.Geophys.,2006,24(11):3173-3177
[20]PU Z Y,ZONG Q G,FRITZ T A,et al.Multiple flux rope events at the high-latitude magnetopause:Cluster/Rapid observation on 26 January,2001[J].Surv.Geophys.,2005,26(1-3):193-214
[21]KHRABROV A V,SONNERUP B U O.Magnetic variance analysis for small-amplitude waves and flux transfer events on a current sheet[J].J.Geophys.Res.,1998,103(A6):11907-11918
[22]HU Qiang,SONNERUP B U O.Reconstruction of magnetic clouds in the solar wind:orientations and configurations[J].J.Geophys.Res.,2002,107(A7):SSH 10-1-SSH10-15
[23]LI H J,FENG X S,ZUO P B,et al.Inferring interplanetary flux rope orientation with the minimum residue method[J].J.Geophys.Res.,2009,114(A3):A03102
[24]RONG Z J,WAN W X,SHEN C,et al.Method for inferring the axis orientation of cylindrical magnetic flux ropebased on single-point measurement[J].J.Geophys.Res.,2013,118(1):271-283
[25]SHI Q Q,SHEN C,PU Z Y,et al.Dimensional analysis of observed structures using multipoint magnetic field measurements:application to Cluster[J].Geophys.Res.Lett.,2005,32(12):L12105
[26]ZHOU X Z,ZONG Q G,PU Z Y,et al.Multiple triangulation analysis:another approach to determine the orientation of magnetic flux ropes[J].Ann.Geophys.,2006,24(6):1759-1765
[27]SHEN C,LI X,DUNLOP M,et al.Magnetic field rotation analysis and the applications[J].J.Geophys.Res.,2007,112(A6):A06211
[28]LI Zhaoyu,CHEN Tao,YAN Guangqing.New method for determining central axial orientation of flux rope embedded within current sheet using multipoint measurements[J].Sci.China Earth Sci.,2016,59(10):2037-2052
[29]FEAR R C,MILAN S E,FAZAKERLEY A N,et al.Motion of flux transfer events:a test of the Cooling model[J].Ann.Geophys.,2007,25(7):1669-1690
[30]SISCOE G L,DAVIS JR L,COLEMAN JR P J,et al.Power spectra and discontinuities of the interplanetary magnetic field:mariner 4[J].J.Geophys.Res.,1968,73(1):61-82
[31]WATSON D F.Contouring:A Guide to the Analysis and Display of Spatial Data[M].New York:Pergamon Press,1992
[32]HASEGAWA H,SONNERUP B U O,OWEN C J,et al.The structure of flux transfer events recovered from Cluster data[J].Ann.Geophys.,2006,24(2):603-618
[33]LUI A T Y.Grad-Shafranov reconstruction of magnetic flux ropes in the near-Earth space[J].Space Sci.Rev.,2011,158(1):43-68
[34]MCFADDEN J P,CARLSON C W,LARSON D,et al.The THEMIS ESA plasma instrument and in-flight calibration[J].Space Sci.Rev.,2008,141(1-4):277-302
[35]AUSTER H U,GLASSMEIER K H,MAGNES W,et al.The THEMIS fluxgate magnetometer[J].Space Sci.Rev.,2008,141(1-4):235-264
[36]DING D Q,LEE L C,MA Z W.Different FTE signatures generated by the bursty single X line reconnection and the multiple X line reconnection at the dayside magnetopause[J].J.Geophys.Res.,1991,96(A1):57-66
[37]REME H,BOSQUED J M,SAUVAUD J A,et al.The Cluster Ion Spectrometry(CIS)experiment[J].Space Sci.Rev.,1997,79(1/2):303-350
[38]BALOGH A,DUNLOP M W,COWLEY S W H,et al.The Cluster magnetic field investigation[J].Space Sci.Rev.,1997,79(1/2):65-91
[39]ESCOUBET C P,SCHMIDT R,GOLDSTEIN M L.Cluster-science and mission overview[J].Space Sci.Rev.,1997,79(1/2):11-32