Magnetic field rotation analysis and the applications

	Magnetic field rotation analysis and the applications
	Shen, C. ; Li, X. ; Dunlop, M. ; Shi, Q. Q. ; Liu, Z. X. ; Lucek, E. ; Chen, Z. Q.
刊名	Journal of Geophysical Research-Space Physics
	2007
卷号	112 期号:A6 页码:A06211
关键词	flux ropes plasma sheet cluster models
ISSN号	0148-0227
通讯作者	北京8701信箱
英文摘要	An analysis technique, termed MRA ( magnetic rotation analysis), has been designed to probe three-dimensional magnetic field topology. It is based on estimating the gradient tensor of four-point measurements of the magnetic field which have been taken by the Cluster mission. The method first constructs the symmetrical magnetic rotation tensor and in general terms deduces the rotation rate of magnetic field along one arbitrary direction. In particular, the maximum, medium, and minimum magnetic rotation rates along corresponding characteristic directions of a magnetic structure can be obtained. The value of the curvature of a magnetic field line, for example, is given by the magnetic rotation rate along the magnetic unit vector and its corresponding radius of curvature is readily obtained. MRA has been applied here to analyze the geometrical structure of two distinct magnetospheric structures, i.e., the tail current sheet and the tail flux rope. The normal of the current sheet is the direction at which the magnetic field has the largest rotation rate. The half thickness of the one-dimensional neutral sheet can also be determined from the reciprocal of the maximum magnetic rotation rate. The advantage of the MRA method is that not only it can determine the orientation but also the internal geometrical configuration and spatial scale of the magnetic structures. A key feature of the MRA method is that it provides the detailed picture of the magnetic rotation point by point through any crossing of the current sheet. As a result, the thickness of the neutral sheet (NS) can be explicitly demonstrated to vary with time, as indicated in one case study, where the NS becomes thicker after the onset of a substorm. MRA has also been applied here to analyze the detailed features of magnetic field variations inside of a flux rope. The principal axis of the flux rope is the direction at which the magnetic field rotates at the least rate. The magnetic scale of the flux rope can also be determined ( about 1R(E) in the case chosen). It is also found that there are both frontside-backside and dawn-dusk asymmetries for the flux rope under study.
学科主题	空间物理
收录类别	SCI
原文出处	http://www.agu.org/pubs/crossref/2007/2005JA011584.shtml
语种	英语
内容类型	期刊论文
源URL	[http://ir.cssar.ac.cn/handle/122/1077]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	Shen, C.,Li, X.,Dunlop, M.,et al. Magnetic field rotation analysis and the applications[J]. Journal of Geophysical Research-Space Physics,2007,112(A6):A06211.
APA	Shen, C..,Li, X..,Dunlop, M..,Shi, Q. Q..,Liu, Z. X..,...&Chen, Z. Q..(2007).Magnetic field rotation analysis and the applications.Journal of Geophysical Research-Space Physics,112(A6),A06211.
MLA	Shen, C.,et al."Magnetic field rotation analysis and the applications".Journal of Geophysical Research-Space Physics 112.A6(2007):A06211.