[en] 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 81⁰2,). In this study, first the cases were selected when a reversal of the sign of the B/sub y/ 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 B/sub y/ negative to B/sub y/ positive. These decreses 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 B/sub y/ reversals from positive to negative. Important vertical and horizontal plasma drift velocities appear in the irregular density variations and especially at localized ioniztion 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