Open AccessStorm and substorm effects on magnetotail current sheet motion
Author(s) -
Davey E. A.,
Lester M.,
Milan S. E.,
Fear R. C.
Publication year - 2012
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 - 10.1029/2011ja017112
Subject(s) - substorm , current sheet , physics , ring current , current (fluid) , plasma sheet , magnetic field , geophysics , heliospheric current sheet , magnetosphere , cluster (spacecraft) , interplanetary magnetic field , solar wind , magnetohydrodynamics , quantum mechanics , thermodynamics , computer science , programming language
Passes through the mid‐region of the magnetotail by the Cluster spacecraft from 2001 to 2007 have been examined to study the dynamics of the cross‐tail current sheet. Cluster is ideally placed to study this region due to the orientation of the orbit in the magnetotail, such that the current sheet is sampled at distances downtail from about 8–19 R E . Multiple fluctuations of the X component of the magnetic field (B X ) from positive to negative and vice versa, measured by Cluster as it crosses the nominal location of the current sheet, indicate that the current sheet is in motion. In this study we use the number of crossings of the current sheet by the Cluster 3 spacecraft as a measure of the dynamics of the magnetotail. The effects of substorm and magnetic storm activity on the dynamics during these orbits have been investigated using the AE and SYM‐H indices. Our results indicate that the current sheet is more often in motion during orbits when there is greater than average substorm activity and a quiet ring current. Results suggest that internal processes within the tail that initiate substorms may also initiate the flapping motion of the current sheet. In addition the more dipolar field that results from an enhanced ring current during magnetic storms may inhibit tail dynamics during substorm events.