During the January 1997 coronal mass ejection/magnetic cloud event, the POLAR spacecraft experienced three successive perigee passes with dramatically different interplanetary magnetic field (IMF) and solar wind conditions on January 9, 10 and 11. The magnetic field observations during these three successive perigee passes are used to examine the response of the low-altitude polar and auroral magnetosphere to different IMF and solar wind conditions. We find that field-aligned currents are controlled mainly by the southward IMF component. They are greatly enhanced during strongly southward IMF conditions on January 10, but the solar wind dynamic pressure has little effect on their strength during the passage of the high-density solar wind filament on January 11. Thus, drag on the magnetosphere is principally due to reconnection at the magnetopause, with little due to viscous effects. Effects of the ring current and the magnetopause current can be identified in the magnetic field data in the low-altitude magnetosphere. During the magnetic storm of January 10, the ring current exhibits strong dawn-dusk asymmetry. It is much stronger in the dusk sector than in the dawn sector. ¿ 1998 American Geophysical Union