We model an interval of sustained northward interplanetary magnetic
field, for which we have a comprehensive set of observational data. This
interval is associated with the arrival of an interplanetary coronal
mass ejection. The solar wind densities at the time are particularly
high and the interplanetary magnetic field is primarily northward. This
results in strong auroral emissions within the polar cap in a cusp spot,
which we associate with lobe reconnection at the high-latitude
magnetopause. We also observe areas of upwards field-aligned current
within the summer Northern Hemisphere polar cap that exhibit large
current magnitudes. The model is able to reproduce the spatial
distribution of the field-aligned currents well, even under changing
conditions in the incoming interplanetary magnetic field. Discrepancies
exist between the modeled and observed current magnitudes. Notably, the
winter Southern Hemisphere exhibits much lower current magnitudes
overall. We also model a sharp transition of the location of
magnetopause reconnection. This changes rapidly from a subsolar location
at the low-latitude magnetopause under southward interplanetary magnetic
field conditions, to a high-latitude lobe reconnection location when the
field is northward. This occurs during a fast rotation of the IMF at the
shock front of a magnetic cloud.