 |
| Titel |
A physical explanation for the magnetic decrease ahead of dipolarization fronts |
| VerfasserIn |
Z. H. Yao, J. Liu, C. J. Owen, C. Forsyth, I. J. Rae, Z. Y. Pu, H. S. Fu, X.-Z. Zhou, Q. Q. Shi, A. M. Du, R. L. Guo, X. N. Chu |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 33, no. 10 ; Nr. 33, no. 10 (2015-10-26), S.1301-1309 |
| Datensatznummer |
250121260
|
| Publikation (Nr.) |
 copernicus.org/angeo-33-1301-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|