Internally and externally induced deformations of the
magnetospheric equatorial current as inferred from spacecraft data
N. A. Tsyganenko, V. A. Andreeva, and E. I. Gordeev
Abstract. Based on a data pool of 79 yearly files of space
magnetometer data by Polar, Cluster, Geotail, and Themis
satellites between 1995 and 2013, we developed a new quantitative
model of the global shape of the magnetospheric
equatorial current sheet as a function of the Earth's dipole tilt
angle, solar wind ram pressure, and interplanetary magnetic
field. This work upgrades and generalizes an earlier model
of Tsyganenko and Fairfield (2004) by extending the modelling
region to all local times, including the dayside sector.
In particular, an essential feature of the new model is
the 'bowl-shaped' tilt-related deformation of the equatorial
surface of minimum magnetic field, similar to that observed
at Saturn, whose existence in the Earth's magnetosphere has
been demonstrated in our recent work (Tsyganenko and Andreeva, 2014).
Accepted for publication by Annales Geophysicae, November 28, 2014.