Electric circuits and their generators in the Earth's magnetosphere: conception of electric circuits as applied to the first phase of 6 April 2000 superstorm

The first phase of 6 April 2000 superstorm was examined on the base of analogy between systems of magnetospheric currents and wire electric circuits. The traditional data set was used as well which was supplemented by maps of ionospheric equivalent currents (EC) and field-aligned currents (FAC). Using this analogy allowed us to take account of spatial R.N-inhomogeneities in a distribution of FAC density in two-dimensional ionosphere, and three types of meridional current systems MCS-0, MCS-1, и MCS-2 which provide an electric link of three Iijima and Potemra FAC zones. On this basis, formation and observed dynamics of ionospheric auroral electrojets and three-dimensional current systems in the disturbed magnetosphere-ionosphere system are described. The obtained results modify known paradigms of substorm current wedge (SCW) conception. The new important fact should be noted that together with the beginning of expansion phase of disturbance generated by abrupt increase in solar wind (SW) dynamic pressure, the similar abrupt increase in polar cap area is observed, as well as the increase in the flux of electromagnetic energy coming from SW into the magnetosphere.