We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
A physical explanation for the magnetic decrease ahead of dipolarization fronts.
- Authors
Yao, Z. H.; Liu, J.; Owen, C. J.; Forsyth, C.; Rae, I. J.; Pu, Z. Y.; Fu, H. S.; Zhou, X.-Z.; Shi, Q. Q.; Du, A. M.; Guo, R. L.; Chu, X. N.
- 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.
- Subjects
POLARIZATION (Nuclear physics); MAGNETOSPHERE; THEMIS (Artificial satellites); CURRENT density (Electromagnetism); PLASMA pressure; MAGNETIC storms
- Publication
Annales Geophysicae (ANGEO) (09927689), 2015, Vol 33, Issue 10, p1301
- ISSN
0992-7689
- Publication type
Article
- DOI
10.5194/angeo-33-1301-2015