Assessment of using field-aligned currents to drive the global ionosphere thermosphere model: A case study for the 2013 St Patrick's Day geomagnetic storm

Without the neutral wind dynamo, the cross-polar-cap potential and hemispheric integrated Joule heating could be underestimated by more than 20%. Moreover, the FAC-driven simulation is able to well reproduce the ionospheric response to the geomagnetic storm in the American sector. However, the FAC-driven simulation yields relatively larger data-model discrepancies compared to the AMIE-driven GITM simulation.

This may result from inaccurate Joule heating estimations in the FAC-driven simulation caused by the inconsistency between the FAC and electron precipitation patterns. This study indicates that the FAC-driven technique could be a useful tool for studying the coupled ionosphere and thermosphere system provided that the FACs and electron precipitation patterns can be accurately specified.