Meridional currents in the equatorial electrojet region

Abstract

The equatorial electrojet model given by Untiedt conceives of a vertical current and therefore a meridional current. Computations are made of ΔX m and ΔY m , measures of electrojet currents flowing towards geomagnetic east and of meridional currents flowing towards geomagnetic north, using the mean hourly values of horizontal force and declination observed at Trivandrum, Kodaikanal, Annamalainagar, Alibag and Huancayo. The meridional currents here computed flow from south to north across the dip equator and are different from the meridional currents in the Untiedt model which are not observable on ground. These currents do not form part of the Sq current system. They flow from south to north in the ionosphere and close circuit in the magnetosphere as was first suggested by Van Sabben. The overhead meridional current intensity is of the order of 30–40 amp/km. The meridional electric field under the electrojet forms about 5–10 per cent of the main east-west electric field. The comparison of the east force at Alibag with the stations under the electrojet reveals that the meridional currents under the electrojet are weaker than those outside it.