Open AccessCharacteristics of storm time electric fields in the inner magnetosphere derived from Cluster data
Author(s) -
Matsui H.,
PuhlQuinn P. A.,
Bonnell J. W.,
Farrugia C. J.,
Jordanova V. K.,
Khotyaintsev Yu. V.,
Lindqvist P.A.,
Georgescu E.,
Torbert R. B.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja015450
Subject(s) - electric field , ring current , physics , magnetosphere , electric current , plasma sheet , computational physics , geophysics , geomagnetic storm , magnetic field , solar wind , quantum mechanics
Storm‐time electric fields in the inner magnetosphere measured by Cluster are reported in this study. First, we show two events around the time when Dst index is at a minimum. The electric field possibly related to subauroral ion drifts and/or undershielding is measured inside the inner edge of the electron plasma sheet in the eveningside. For the second event observed in the nightside, the electric field is partly related to dipolarization and is considered as inductive. An electric field without coincident magnetic signatures is also observed. Spatial coherence of the electric field is not large when we check multispacecraft data. It is inferred that the electric field in the magnetotail penetrates inside the region 1 current, while it is not clear about the electric field within the region 2 current from our data. Then superposed epoch analyses using 71 storms are performed. Electric fields at R = 3.5–6 R E and less than 25 degrees of magnetic latitudes are enhanced around the minimum Dst at all magnetic local times. Electric fields during the recovery phase decay on a time scale shorter than that of Dst index, which could be interpreted in terms of the relation between electric field and ring current during that storm phase. AC electric fields are generally larger than DC electric fields, indicating that the former component might play some role in accelerating ring current particles. These results will be useful to update our empirical electric field model.