The auroral oval is the site of ionospheric electric currents, some of which diverge into and out of the ionosphere to flow as Birkeland currents along the magnetic lines of force. The currents flowing parallel to the contours of the oval are known as the auroral electrojets, and their strength reflects the combined effect of ionospheric conductivity and the electric field. In this paper we show quantitatively the variation of the poleward and equartoward borders of the auroral electrojets as a function of the level of magnetospheric activity as quantified by the AE index. We find the latitudinal width of the electrojets to be relatively constant over levels of magnetic activity ranging over AE values of up to ~500 nT. The eastward and westward electrojets, while retaining a constant width of ~6¿, both expand equatorward with increasing magnetospheric activity; however, the equatorward shift is much more pronounced for the eastward jet than for the westward one, particularly in the dusk sector. |