Creation of the substorm current wedge through the perturbation of the directly driven current system: a new model for substorm expansion

G. Rostoker (1) , E. Friedrich (1)

1 Department of Physics [Edmonton]

The past four decades have seen a considerable amount of research on the study of magnetospheric substorms, and over most of these years the expansive phase of the substorm has been associated with the development of a three dimensional current system that has been termed the substorm current wedge. This current system has been thought to be a consequence of the short-circuiting of crosstail current through the ionosphere, and is viewed as a distinctive current system operating independently from the directly driven current with which it co-exists. The purpose of this paper is to show that the substorm current wedge should be viewed as an equivalent current system rather than a real current system. It will be shown that the magnetic perturbation pattern associated with the current wedge can be modeled as purely a perturbation of the directly driven current system in the midnight sector.

Keywords. Magnetospheric physics (Auroral phenomena; Current systems; Magnetotail; Storms and substorms

Domaines: Océan, Atmosphère; Sciences de la Terre

G. Rostoker, E. Friedrich. Creation of the substorm current wedge through the perturbation of the directly driven current system: a new model for substorm expansion. Annales Geophysicae, 2005, 23 (6), pp.2171-2182. ⟨hal-00317855⟩