Storm-time Interactions between the Ionosphere and Thermosphere

A new 3-dimensional coupled model of the global Ionosphere and Thermosphere has been developed with the main focus of addressing the challenge of understanding and predicting the response of the coupled Ionosphere-Thermosphere system to geomagnetic storms. The model can be applied to such global scale phenomena as traveling atmospheric disturbances (TADs), traveling ionospheric disturbances (TIDs), which are associated with geomagnetic storms and substorms. TADs play a significant role in changing the global circulation, redistributing the energy and momentum of magnetospheric origin, from high to lower latitudes, and modifying the electrodynamics. The storm-time simulations demonstrate that the neutral atmospheric disturbances propagate to lower latitudes with strong LT dependences. The propagation properties are controlled by ion-drag, represents one of the key interaction processes between the neutral and ionized species, and is determined by both the plasma density and drift. At the same time, the plasma density and drift respond to the altered electrodynamics, as well as the neutral atmospheric disturbances. Changes in ion-drag affect the global propagation of the neutral atmospheric disturbances and establishment and temporal evolution of the global circulation. The global coupled model is a valuable resource to help elucidate the interacting processes in the time-dependent coupled system of the global thermosphere and ionosphere.