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Ann. Geophys., 21, 1947-1953, 2003
www.ann-geophys.net/21/1947/2003/
© European Geosciences Union 2003
Magnetic turbulence and particle dynamics in the Earth’s magnetotail
G. Zimbardo1,*, A. Greco1,*, A. L. Taktakishvili2, P. Veltri1,*, and L. M. Zelenyi3
1Physics Department, University of Calabria, Ponte P. Bucci, Cubo 31C, I-87036 Rende, Italy
2Abastumani Astrophysical Observatory, A. Kazbegi str., 2a, 380060, Tbilisi, Georgia
3Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
*also at: Istituto Nazionale di Fisica della Materia, Unita’ di Cosenza, Italy
Abstract. The influence of magnetic
turbulence in the near-Earth magnetotail on ion motion is investigated by
numerical simulation. The magnetotail current sheet is modelled as a magnetic
field reversal with a normal magnetic field com-ponent Bn , plus a
three-dimensional spectrum of magnetic fluctuations dB
which represents the observed magnetic turbulence. The dawn-dusk electric
field Ey is also considered. A test particle simulation is performed
using different values of Bn and of the fluctuation level dB/B0.
We show that when the magnetic fluctuations are taken into account, the
particle dynamics is deeply affected, giving rise to an increase in the cross
tail transport, ion heating, and current sheet thickness. For strong enough
turbulence, the current splits in two layers, in agreement with recent Cluster
observations.
Key words. Magnetospheric physics (magnetospheric
configuration and dynamics) – Interplanetary physics (MHD waves and
turbulence) – Electromagnetics (numerical methods)
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