Field-aligned current as a possible source for ΔB observed by low-altitude satellites

This note proposes that the ΔB measured by low-altitude satellites (the scalar magnitude difference in the geomagnetic field intensity above the ionosphere and that extrapolated from the quiet-time ground data) in high latitudes on quiet days may be explained by an effect of permanent field-aligned currents flowing into the ionosphere in the dawn region and leaving the ionosphere from the dusk region to maintain the geomagnetic Ssub(q)sup(p)-field. (auth.)