Electrodynamic coupling effects in the thermosphere/ionosphere system

Abstract

Thermospheric winds have a strong influence on the dynamics and electrodynamics of the ionosphere, and in return, ionospheric electrodynamic processes feed back onto the dynamics of the thermosphere. Observations of geomagnetic variations and ionospheric electric fields can provide valuable information about the distribution and variability of upper atmospheric winds systems, including atmospheric tides and planetary waves that propagate into the ionosphere from the middle atmosphere. The observations can lead to inferences about the generation and propagation conditions of those global waves in the lower and middle atmosphere, and hence provide information concerning changes in the state of the global atmosphere. Realistic simulation modeling of ionospheric electrodynamic effects must take into account the interactions between neutral and plasma dynamics, as is done in the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model. At low latitudes, the mutual coupling among neutral dynamics, ionospheric plasma dynamics, electrical conductivities, electric fields, and currents strongly affects the behavior of the thermosphere and ionosphere. At high latitudes, thermospheric and ionospheric phenomena are also strongly coupled to magnetospheric electrodynamics.