Ionospheric current system associated with the equatorial counterelectrojet

Abstract

The phenomenon of the equatorial counterelectrojet current (CEJ) is studied utilizing the D, H, and Z components of the magnetic field at a chain of geomagnetic observatories in the Indo-Russian zone extending from 0 to 75° N magnetic dip. Very significant changes in both H and D components are shown to occur on CEJ days at all stations even north of Sq focus. The current system associated with CEJ consists of two vortices, one counterclockwise in the morning and another clockwise in the evening hours. The counterelectrojet events during December solstices seem to be associated with the disappearance of the Sq current loop in the Indo-Russian sector and on a number of consecutive days. The cause of the counterelectrojet is suggested to be the changes in various modes of the tidal movements in the upper atmosphere.