Keywords:Equatorial Plasma Bubble, Penetration Electric Field, Magnetosphere-Ionosphere Coupling, Geomagnetic Storm
In the equatorial and low latitude ionosphere, the equatorial ionization anomaly (EIA) is the most striking large-scale phenomenon. Embedded within EIA are smaller-scale low-density structures, i.e., the equatorial plasma bubbles (EPBs). EPBs are known to host ionospheric irregularities that can cause severe satellite signal scintillations and even signal loss of lock, thereby affecting communication and navigation. However, our understanding of the day-to-day and longitudinal variability of EIA and EPBs is still illusive. During geomagnetic disturbances, energy and momentum from the solar wind and the magnetosphere largely deposit in the high-latitude region, while their impact can propagate to the mid-latitude to equatorial regions in multiple ways to affect EPB dynamics, including prompt penetrating electric field (PPEF), disturbance winds and the associated dynamo electric field (DDEF), and traveling atmosphere disturbances and their ionosphere manifestations (TADs/TIDs). In recent years, the rapidly developing ground-based GNSS receiver network has enabled regional to continental scale measurements of the ionosphere and has revealed rich dynamic structures in those regions during storm time, such as much widened or asymmetric EIA crest and super equatorial plasma bubbles reaching relatively high latitudes. In this talk, we will discuss our recent findings about the knowns and unknowns of EPB dynamics, such as the dynamic evolution of the super bubble event during the Sep. 7, 2017 storm.