Characterising the electron density fluctuations in the high-latitude ionosphere at Swarm altitude in response to the geomagnetic activity

Abstract

The high−latitude ionosphere is characterised by plasma density irregularities with typical lengths in a wide range of scales (from ~1 m up to ~1000 km). The enhancement of these irregularities caused for instance by severe Space Weather conditions can affect trans−ionos− pheric communications between ground facilities and satellites. For this reason, an accurate characterisation of the dynamic properties of electron density and their variation with the geomagnetic activity level is of particular interest for the Space Weather especially at high latitudes. In this framework, taking advantage of high resolution in situ measurements by the recent ESA−Swarm space mission orbiting in the ionospheric F−layer, we study both the dynamical properties of the electron density and the scaling properties of the electron den− sity fluctuations at high latitudes in the Northern and Southern Hemispheres in response to changes in the geomagnetic activity levels via nonlinear techniques involving the first−order structure functions. Indeed, it has been shown that the turbulent character of the ionos− pheric plasma density plays an important role in the generation and dynamics of ionospheric plasma density irregularities and the study of the scaling properties of the electron density fluctuations permits us to characterise the possible turbulent state of the ionospheric elec− tron density. The obtained results are consistent with the turbulent character of the ionospheric dynamics, and with the presence of dif− ferent turbulent regimes that show a dependence on the geomagnetic activity levels, magnetic latitude and MLT values.