Measurements of the ion convection velocity (transverse horizontal and vertical components) from asymmetry of the lateral ion flow in the satellite frame and also of the total ion concentration were conducted in October-November 1967 from the Cosmos 184 satellite (circular orbit at 630 km, inclination 81ø2'). In this study, first the cases were selected when a reversal of the sign of the By component of the IMF had taken place during the time interval between two successive satellite passes through the equatorial ionospheric anomaly (11 cases). Systematic decreases of the near-equatorial ion density were observed after reversals from By negative to By positive. These decreases were accompanied by relative enhancements of the upward and the eastward components of the plasma drift velocity of the order of several tens of meters per second. Variations of the opposite direction were observed (though less regularly) after By reversals from positive to negative. Important vertical and horizontal plasma drift velocities appear in the irregular density variations and especially at localized ionization spikes (downward velocity relative to surrounding plasma) and dropouts (upward relative velocity). These density dropouts are very similar to the 'plasma bubbles' reported by McClure et al. (1977) and at 630 km are observed mostly when the density profile has a near-equatorial valley. It was shown by Heppner (1972) that the polar cap convection pattern depends on the sign of the By IMF component. If follows that suitably selected polar plasma drift data from Cosmos 184 can also be used to find the pairs of orbits indicating the reversals of By IMF ('inferred reversals'). Typical signatures of the plasma drift pattern in the noon region close to the southern (sunlit) dayside polar cusp were constructed from the whole set of Cosmos 184 data. These signatures indeed show high correlation with the sign of By IMF. The reversal of typical signatures on a pair of successive orbits in fact represents the direct indication of the large-scale electric field variation in the polar ionosphere/outer magnetosphere presumably induced by the reversals of By IMF (9 cases partly overlapping the 11 cases mentioned above). The two sets of data (pairs of orbits) are in general accord (with several doubtful cases but no direct contradictions) both with respect to the By sign reversal evaluation and with respect to the above-described differential variations in the latitudinal ion density profiles and in the plasma drift velocities in the equatorial ionospheric anomaly. These observations confirm the propagation of the electric field variations from polar ionosphere/outer magnetosphere down to the equatorial latitudes, as was suggested by Rastogi and Patel (1975).