Multifractal structure and intermittence in the AE index time series

The conventional approach to magnetospheric dynamics has not provided until now a satisfactory description of the singular behaviour of magnetospheric substorms. In this paper we present a multifractal analysis of AE time series, based on singularity analysis, a new tool to investigate signal dynamics features. The existence of a multifractal structure of the AE index with respect to time dilation has been investigated. The resulting multifractal behaviour of the signal can be interpreted as the signature of an underlying intermittence phenomenon. The derived singularity spectrum is well in agreement with the one of a two-scale Cantor model (P-model), a pure multiplicative model. The presence of intermittence in AE might indicate the occurrence of turbulence in magnetospheric dissipation processes.