Electric field and wind motion at the magnetic equator

The vertical electric field due to charge separation is calculated for a horizontal wind motion periodic with height, latitude, and longitude under magnetical equatorial conditions. It is found that the electric field is less than (W × B0) in magnitude at the magnetic equator in the presence of the curved lines of force of geomagnetic field B0, where W is the wind velocity. Thus the (W × B0) field at the equator directly contributes to driving the equatorial electrojet; the driving electric field is not curl free. The wind shear mechanism for producing ionization irregularities is still effective at the equator, but of lower efficiency than at mid-latitudes. Certain observations are consistent with the present conclusion.