UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

A physical explanation for the magnetic decrease ahead of dipolarization fronts

Yao, ZH; Liu, J; Owen, CJ; Forsyth, C; Rae, IJ; Pu, ZY; Fu, HS; ... Chu, XN; + view all (2015) A physical explanation for the magnetic decrease ahead of dipolarization fronts. Annales Geophysicae , 33 (10) pp. 1301-1309. 10.5194/angeo-33-1301-2015. Green open access

[thumbnail of angeo-33-1301-2015.pdf]
Preview
Text
angeo-33-1301-2015.pdf - Published Version

Download (1MB) | Preview

Abstract

Recent studies have shown that the ambient plasma in the near-Earth magnetotail can be compressed by the arrival of a dipolarization front (DF). In this paper we study the variations in the characteristics of currents flowing in this compressed region ahead of the DF, particularly the changes in the cross-tail current, using observations from the THEMIS satellites. Since we do not know whether the changes in the cross-tail current lead to a field-aligned current formation or just form a current loop in the magnetosphere, we thus use redistribution to represent these changes of local current density. We found that (1) the redistribution of the cross-tail current is a common feature preceding DFs; (2) the redistribution of cross-tail current is caused by plasma pressure gradient ahead of the DF and (3) the resultant net current redistributed by a DF is an order of magnitude smaller than the typical total current associated with a moderate substorm current wedge (SCW). Moreover, our results also suggest that the redistributed current ahead of the DF is closed by currents on the DF itself, forming a closed current loop around peaks in plasma pressure, what is traditionally referred to as a banana current.

Type: Article
Title: A physical explanation for the magnetic decrease ahead of dipolarization fronts
Open access status: An open access version is available from UCL Discovery
DOI: 10.5194/angeo-33-1301-2015
Publisher version: http://dx.doi.org/10.5194/angeo-33-1301-2015
Language: English
Additional information: © Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License.
Keywords: Magnetospheric physics, current systems, magnetotail, plasma sheet
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/1475223
Downloads since deposit
91Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item