Abstract

We present a statistical model of the ionospheric electric field derived from line-of-sight plasma velocity measurements from the Super Dual Auroral Radar Network (SuperDARN). Electric field patterns are produced using an established technique that models the electric field as a spherical harmonic expansion of the ionospheric electric potential. Major improvements over existing models are achieved by the use of novel parameterisations that capture three major sources of time-variability of the coupled solar wind-magnetosphere-ionosphere system: 1) the upstream solar wind conditions, specifically the strength and orientation of the interplanetary magnetic field and the steadiness of the solar wind, 2) substorm onset location as well as the time relative to substorm onset, and 3) the variability introduced by geomagnetic storms. These account for the variability in the magnetosphere-ionosphere system, which occurs even under continuous steady driving by the solar wind. The second source of variability relates to the storage and release of energy in the magnetosphere that is associated with magnetospheric substorms. The electric field evolves throughout the substorm cycle and geomagnetic storm phases, and its morphology is strongly influenced by their occurrences. We discuss the details of the model, and assess its performance by comparison to other models and to observations.