Horizontal Wind Systems in the Ionospheric E Region Deduced from the Dynamo Theory of the Geomagnetic Sq Variation

Abstract

Horizontal wind systems in the ionospheric E-region are obtained from the dynamo theory of the solar daily magnetic variation on quiet days, for the case of a non-rotating earth. It is found that the main harmonicterm of ionospheric wind velocities necessary to produce the quiet-day magnetic variations is not semi-diurnal, but diurnal. The diurnal amplitude is about 30m/sec and the semi-diurnal one is about 10m/sec at low latitudes. The semi-diurnal component is nearly in phase with that of winds on the ground derived from the barometric pressure variation, and its tidal amplification is estimated as about 50. On the basis of these ionospheric winds, the vertical drift velocities of electrons in the F-region are estimated.