The investigators will use a coupled thermosphere-ionosphere-plasmasphere model to study the low latitude thermosphere and ionosphere under quiet and magnetically disturbed conditions. The purpose is to understand the interactions between dynamics, plasma density, and electrodynamics in response to geomagnetic storms. The quiet-time low latitude thermosphere and ionosphere exhibit interesting feedback interactions that give rise to features such as the equatorial ionization anomaly, the pre-reversal enhancement of the eastward electric field, high velocity neutral winds at the magnetic equator, neutral peaks in the post sunset anomaly, and large vertical winds co-located with the temperature features. During a geomagnetic storm, changes in the magnetosphere affect the atmosphere through electric fields that redistribute ionization. This in turn modifies neutral winds and atmospheric composition. The researchers will attempt to simulate these effects using a sophisticated model that couples the thermosphere, ionosphere, and plasmasphere, and they will test the results using ground- and space-based measurements.