Polarization fields produced by winds in the equatorial F-region

Neutral air winds blowing across the magnetic field cause a slow transverse drift of the positive ions, perpendicular to both the winds and the magnetic field. This drift sets up an electric polarization field which can only be neutralized by currents flowing along magnetic field lines and through the E-layer. But at night the E-layer conductivity may be too small to close this circuit, so that polarization fields build up in the F-layer, causing the plasma to drift with the wind. This polarization effect may influence the behaviour of the nighttime equatorial F-layer and contribute to ‘superrotation’ of the atmosphere.