Field-aligned currents in the dayside cusp and polar cap region during northward IMF

[1] The field-aligned currents in the dayside cusp and polar cap region are examined using magnetic data from the low-altitude polar-orbiting satellite Orsted. The study is confined to cases where the interplanetary magnetic field (IMF) has a steady northward component and to a rather narrow region spanning ∼4 hours around magnetic noon. We examine individual passes using a maximum variance analysis method, and we complement, for a single event, with ground-based data from the Greenland meridian chain of magnetometers. We suggest that when an east-west component By of the IMF exists for positive IMF Bz, the two NBZ (northward Bz) field-aligned currents that prevail over the polar region rotate to form the two field-aligned currents equatorward and poleward of the east-west flowing ionospheric DPY current in the dayside. The high accuracy of the Orsted data makes it possible to uncover details not previously described.