Variability of ionospheric plasma observed by the Swarm satellites within high latitude regions

The high-latitude ionosphere is a complex plasma containing electron density structures with a range of spatial scale sizes. The largest of these scale structures can extend for tens to hundreds of kilometres in the horizontal direction, and exhibit variations dependent upon factors such as: time of day, season, solar cycle, geomagnetic activity, solar wind activity and location. These large-scale structures can give rise to much smaller scale structure irregularities due to instability processes. These smaller-scale structures can disrupt trans-ionospheric radio signals, including those used by Global Navigation Satellite Systems (GNSS). While the processes that drive these structures are well understood, the relative importance of these driving processes, is a fundamental unanswered question.
Swarm is ESA's first constellation mission for Earth Observation (EO). It initially consisted of three identical satellites (Swarm A, Swarm B, and Swarm C), which were launched into near-polar orbits on 22 November 2013. Initially Swarm A and C were at an altitude of 462 km and at an inclination angle of 87.35°. Swarm B was in a higher orbit with an initial altitude of 511 km and an inclination angle of 87.75°. This unique configuration, in combination with the data products developed for dataset from individual satellites, enables studies of the spatial variability of the ionosphere.
The Swarm-VIP (Variability of Ionospheric Plasma) project aims to characterise the ionospheric plasma and the dynamical coupling between different scales in the ionosphere in response to the driving processes. Previous studies have developed data products which quantify the variability of ionospheric plasma on a range of spatial scale sizes. In this work we present a generalised linear modelling (GLM) approach to relate these high-latitude structure to the driving processes. The models developed determine which conditions perturb the ionosphere from a quiet state, and hence which conditions drive extreme events, and how these vary with the scale size of the structures.