Yao, ZH; Liu, J; Owen, CJ; Forsyth, C; Rae, IJ; Pu, ZY; Fu, HS; ... Chu, XN; + view all Yao, ZH; Liu, J; Owen, CJ; Forsyth, C; Rae, IJ; Pu, ZY; Fu, HS; Zhou, X-Z; Shi, QQ; Du, AM; Guo, RL; Chu, XN; - view fewer (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.

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.

Download activity - last month

Export as XMLJSONCSV

Download activity - last 12 months

Export as XMLJSONCSV

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item