Fractal dynamics of the geomagnetic activity AE index as possible manifestation of self-organized criticality in the magnetosphere

The nature of low-frequency fluctuations of the geomagnetic activity AE index is investigated. It is shown that the AE index dynamics can not be explained by the effect of solar wind parameter variations on processes in the magnetosphere. A hypothesis is proposed of the internal mechanism of fluctuation generation in the current layer of the magnetosphere tail. The hypothesis is based on the theory of self-organized criticality