Passes of the Polar spacecraft through the region-2 field-aligned currents at geocentric distances from 1.7 to 2.3 Earth radii in the southern hemisphere are used to measure the magnetic perturbation associated with these currents. Examination of the interplanetary electric field (IEF) measured by ACE and Wind reveals a linear dependence of the strength of the region-2 currents on the east–west component of the IEF when it is from dawn to dusk and no dependence when it is from dusk to dawn. Thus in the steady-state conditions examined herein, the region-2 currents exhibit a linear dependence on the dawn–dusk component of the IEF as do the ring-current injection and the cross-polar-cap potential drop. Examination of the state of illumination of the ionosphere at the foot of the magnetic field line through Polar reveals that the dependence of the field-aligned currents on the IEF has on average twice the slope for the sunlit ionosphere (387nT/mV) than for the dark ionosphere (175nT/mV). We interpret the result as consistent with the expected greater drag on the convective flow over the sunlit regions than at night due to the greater Pedersen conductivity in sunlight.