Field-aligned current mapping and the problem of the generation of magnetospheric convection

The solution of the problem of the generation of large-scale two-cell magnetospheric convection requires the understanding of the nature of Region 1 currents of Iijima and Potemra [The amplitude distribution of field-aligned currents at northern high latitudes observed by Triad. J. Geophys. Res. 81 (13), 2165–2174, 1976]. The azimuthal distribution of Region 1 currents is analyzed. The picture of field-aligned currents is mapped to the equatorial plane using Tsyganenko-96 and Tsyganenko-2001 magnetic field models. It is shown that the majority of Region 1 currents is mapped to the plasma sheet. The possible contribution of boundary layer processes to the generation of Region 1 currents is evaluated. Additional support of the action of the mechanism of “magnetospheric topology” generation of magnetospheric convection is obtained. Field-aligned currents in accordance with this mechanism are generated due to the existence of the plasma pressure gradients along the isosurfaces of magnetic flux tube volume. Such gradients appear due to the day–night magnetospheric asymmetry.