On the formation of electric fields and currents in the three-dimensional magnetosphere

One of the main still unresolved problems of the Earth's magnetosphere physics is the problem of dawn-dusk electric field formation and interplanetary magnetic field (IMF) control of its value. Analyzing the configuration of magnetic flux tube volume isosurfaces and tail current distribution it became possible to show that the existence of azimuthal plasma pressure gradients and thus field-aligned currents is the intrinsic property of magnetospheric trap connected with its day-night asymmetry. The IMF control of Region I currents can be explained by IMF control of magnetopause and tail currents.