ИСТИНА

A circuit analogy for the magnetosphere-ionosphere current systems has two extremes for drivers of ionospheric currents: the “voltage generator” (ionospheric electric fields/voltages are constant while current varies) and the “current generator” (current is constant while the electric field varies). Here we indicate another aspect of magnetosphere - ionosphere interaction which should be taken into account when considering the current/voltage dichotomy. We show that non-steady field-aligned currents interact with the ionosphere in a different way depending on a forced driving or resonant excitation. A quasi-DC driving corresponds to a voltage generator, when the ground magnetic response is proportional to the ionospheric Hall conductance. The excitation of resonant field line oscillations corresponds to the current generator, when the ground magnetic response practically does not depend on the ionospheric conductance. According to the suggested conception such phenomena as Traveling Convection Vortices should be considered as resonant response of the magnetospheric field lines and they correspond to current generator. Quasi-DC non-resonant disturbances such as Sudden Commencement correspond to voltage generator. Although, there quite a few factors may obscure the determination of the current/voltage dichotomy.