Ionospheric Dynamo Currents and Magnetic Perturbations at the Ground and Above the Ionosphere Modeled by the TIEGCM

The National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General-Circulation Model (TIEGCM) is used to study the spatial and universal-time variations of electric currents generated by the ionospheric wind dynamo, and their associated geomagnetic perturbations at the ground and at low-Earth-orbit (LEO) altitudes. By comparing the geomagnetic perturbation at the ground with geomagnetic data the influence of the distorted geomagnetic-field can be studied and the importance of tidal winds, contributing to the ionospheric wind dynamo, can be examined. The magnetic perturbations at LEO altitudes can be approximated by considering the field-aligned currents flowing between the northern and southern hemisphere at low and middle latitudes. We will study the patterns of the field-aligned currents and the associated magnetic perturbation for quiet conditions and examine and discuss the influence of the tidal winds.