Correlation between ionospheric drift motions measured at low dip latitudes by the ion-cloud technique and at the equator by incoherent scatter

Abstract

The Max-Planck-Institut für extraterrestrische Physik, Munich, Germany, and the National Commission on Space Research from Argentina conducted cooperative experiment involving the release of barium and europium clouds at altitudes between 140 and 250 kn. Three rockets were launched from. Chamical, Argentina (14.9° Dip Lat) in November 1972. Electric fields of the order of 2.0 mV/m were deduced from the ion cloud drifts during evening twilight and 0.5 mV/m during morning twilight. If projected along field lines to the magnetic equatorial plane the drift velocities can be compared with velocities measured simultaneously with the incoherent scatter radar at Jicamarca and with earlier measurements at the magnetic equator. This comparison suggests that the times of reversal of the vertical and horizontal velocities during evening and morning hours depend on altitude in the sense that the reversals occur earlier at greater heights.