A Third Generation Field-Aligned Current Model

Abstract

A new empirical model of field-aligned currents in the Earth's ionosphere has been developed. This model is derived using magnetometer data from the CHAallenging Minisatellite Payload, Ø rsted, and Swarm satellite missions, which has created a database that spans more than 15 years. These data have been associated with solar wind conditions using the Advanced Composition Explorer satellite, as well as the (Formula presented.), (Formula presented.), (Formula presented.), and (Formula presented.) solar indices. With the wealth of data and associated driving conditions, this model has been developed to reproduce field-aligned current maps of the ionosphere based on solar wind electric field, interplanetary magnetic field clock angle, dipole tilt angle, solar index, and geographic hemisphere. This model was constructed using a series of spherical cap harmonic analysis fits based on small selections of the overall database. The coefficients of these fits were then used to develop a model that would reproduce these coefficients based on the previously described driving conditions. One of the most notable improvements demonstrated by this model is the ability to show distinct current regions in the ionosphere, particularly with respect to Region 0 currents during northward (Formula presented.) and highly positive or negative (Formula presented.).