Bifurcated current sheet : model and Cluster observations, Planet

Cluster observations have recently confirmed previous ISEE and Geotail observa-tions showing that the magnetotail current sheet can present a bifurcated structure with two off-centre current peaks. We show in this paper that such a structure can be described by a kinetic tangential equilibrium which is an exact solution of the Vlasov-Maxwell equations. A tangential equilibrium is characterized by a bulk plasma velocity and magnetic field perpendicular to the density and/or tempera-ture gradient direction. The particle distribution functions are sums of an infinite number of elementary functions parametrized by a vector potential. The model is consistent with Cluster observations of a plasma density plateau between the cur-rent peaks and the typical size and amplitude of the current distribution. We briefly review existing models and propose some studies which could be carried out with our model