Average Ionospheric Electric Field Morphologies During Geomagnetic Storm Phases

Abstract

We utilize principal component analysis to identify and quantify the primary electric potential morphologies during geomagnetic storms. Ordering data from the Super Dual Auroral Radar Network (SuperDARN) by geomagnetic storm phase, we are able to discern changes that occur in association with the development of the storm phases. Along with information on the size of the patterns, the first six eigenvectors provide over ∼80% of the variability in the morphology, providing us with a robust analysis tool to quantify the main changes in the patterns. Studying the first six eigenvectors and their eigenvalues shows that the primary changes in the morphologies with respect to storm phase are the convection potential enhancing and the dayside throat rotating from pointing toward the early afternoon sector to being more sunward aligned during the main phase of the storm. We find that the ionospheric electric potential increases through the main phase and then decreases once the storm phase begins. The dayside convection throat points toward the afternoon sector before the main phase and then as the potential increases throughout the main phase, the dayside throat rotates toward magnetic noon. Furthermore, we find that a two-cell convection pattern is dominant throughout and that the dusk cell is overall stronger than the dawn cell.