Flattened current sheet and its evolution in substorms

	Flattened current sheet and its evolution in substorms
	Shen, C. ; Liu, Z. X. ; Li, X. ; Dunlop, M. ; Lucek, E. ; Rong, Z. J. ; Chen, Z. Q. ; Escoubet, C. P. ; Malova, H. V. ; Lui, A. T. Y. ; Fazakerley, A. ; Walsh, A. P. ; Mouikis, C.
刊名	Journal of Geophysical Research-Space Physics
	2008
卷号	113 期号:A7 页码:A07S21
关键词	thin current sheets interplanetary magnetic-field magnetotail current sheet explosive growth-phase tail current sheet plasma sheet cluster measurements sudden enhancement earth magnetotail geomagnetic tail
ISSN号	0148-0227
通讯作者	北京8701信箱
英文摘要	In this research, the properties of a tail current sheet, which has a flattened geometry, and its evolution during substorm activity have been investigated. The geometrical configuration of the magnetic field and the spatial distribution of the current density in a flattened current sheet have been revealed with certainty for the first time. It is found that such a flattened current sheet has sufficiently strong B-y (GSM) within its neutral sheet that the magnetic field lines (MFLs) in the neutral sheet are lie almost in the GSM equatorial plane and that the normal directions are generally northward. Detailed analyses show that, the magnetic field lines are spiral-like, not plane curves, which are left-handed or right-handed spirals for B-y > 0 or B-y < 0. This magnetic rotation occurs predominantly in the neutral sheet. The flattened current sheet may be very thin, and the thickness of the neutral sheet is much less than the minimum radius of the curvature of the MFLs in the current sheet. The analysis also suggests that the neutral sheet current is field-aligned and lies mainly duskward. The curvature current makes little contribution to the total current in the flattened current sheet. The main current carriers in the neutral sheet of the flattened current sheet are electrons. A statistical survey shows that there is one positive correlation between B-y in the flattened current sheet and IMF B-y and penetration efficiency is 0.67. Flattened current sheets may occur in both quiet and disturbed periods and may appear at all phases of the substorms. During the growth phase of a substorm event, the neutral sheet of the flattened current sheet is shown to become progressively thinner, while the associated current density is increasing gradually. It is found that the northern turning of the IMF has triggered the explosive growth phase at the end of the growth phase, which lasts several minutes. At the explosive growth phase, the flattened current sheet becomes much thinner and the current density in the neutral sheet then increases considerably and reaches a value larger than 0.017 mu Am-2. Just after the onset of the substorm, the current density in the neutral sheet drops abruptly and varies turbulently.
学科主题	空间物理
收录类别	SCI
原文出处	http://www.agu.org/pubs/crossref/2008/2007JA012812.shtml
语种	英语
内容类型	期刊论文
源URL	[http://ir.cssar.ac.cn/handle/122/1107]
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.,Liu, Z. X.,Li, X.,et al. Flattened current sheet and its evolution in substorms[J]. Journal of Geophysical Research-Space Physics,2008,113(A7):A07S21.
APA	Shen, C..,Liu, Z. X..,Li, X..,Dunlop, M..,Lucek, E..,...&Mouikis, C..(2008).Flattened current sheet and its evolution in substorms.Journal of Geophysical Research-Space Physics,113(A7),A07S21.
MLA	Shen, C.,et al."Flattened current sheet and its evolution in substorms".Journal of Geophysical Research-Space Physics 113.A7(2008):A07S21.