Upper panel: Ionosphere Equivalent Currents (IEC), which indicate auroral electrojet activity (positive: eastward electrojet, negative: westward electrojet). Middle Panel: Field Aligned Currents (FAC), derived from MFACE model. Lower panel: S variable obtained from the Field Aligned Currents derived from Swarm constellation. Latitude coordinates correspond to the coordinates of Swarm satellites (vertical projection to the ground). Estimates of equatorward auroral oval boundaries and their geographic latitudes are indicated as black horizontal lines.