Previous studies of the Ogo 6 electric field data by Heppner and of magnetic field magnitude observations by Langel have indicated a distinct dependence of disturbance characteristics on interplanetary sector polarity. Examination of simultaneous data below 600 km over the summer polar cap shows that changes in electric field patterns and in the disturbance patterns in magnetic field magnitude ΔB are highly correlated. This correlation extends to pattern shapes, to boundary locations, and to the amplitudes of the correlated quantities. In the winter hemisphere at altitudes 800 km, correlations between boundaries exist, pattern correlations are present but are not as strong as they are at low altitudes in summer, and amplitude correlations are essentially absent. These studies verify that below 600 km the region of positive ΔB, from 2200 to 1000 magnetic local time (MLT), receives a significant contribution from both ionospheric and nonionospheric sources. Above 800 km the nonionospheric sources dominate. These data also are consistent with the existence of a latitudinally broad current system at sunlit magnetic local times as the source of the negative ΔB region between 1000 and 2200 MLT. In this region, broad structures in electric field patterns and in ΔB patterns are highly correlated. Multiple peaks in the negative ΔB, presumably to be identified with the multiple peaks in negative ΔZ found by Langel (1973) in average surface data, occur when the electric field patterns has multiple reversals near dus