Scaling features of geomagnetic field’s fluctuations as indicators of magnetospheric conditions

Author: Paola De Michelis
Affiliation: Istituto Nazionale di Geofisica e Vulcanologia – Via di Vigna Murata 605, Roma Italy

Abstract:
The activity of Earth’s magnetosphere is characterised by sporadic perturbations involving broad ranges of spatial and temporal scales. The characteristics of the geomagnetic signals associated with magnetospheric activity depend on geomagnetic disturbance level and consequently on the interaction level between the solar wind and the Earth’s magnetic field.
Dynamical changes in the scaling properties of the magnetic field fluctuations are found to occur both near the storm onset and during its evolution as well as for different interplanetary magnetic field conditions. We discuss the dynamical changes of the scaling properties of the magnetic field fluctuations at small temporal scale using data from a large number of ground-based geomagnetic observatories in the Northern Hemisphere and recorded by the three satellites of the Swarm constellation. We discuss the dynamical changes in relation to the overall ionospheric polar convection and potential structures as reconstructed using SuperDARN data.
The obtained results are an example of the capability of geomagnetic field fluctuations data to provide new insights about ionospheric dynamics and ionosphere-magnetosphere coupling. At the same time, these results could open doors for development of new applications where the dynamical changes of the scaling properties of magnetic fluctuations are used as local indicators of magnetospheric conditions.

This work is partially supported by the Italian National Program for Antarctic Research (PNRA) Research Project 2013/AC3.08