Meridional equatorial electrojet current in the American sector

Huancayo is the only equatorial electrojet station where the daytime increase of horizontal geomagnetic ®eld (H) is associated with a simultaneous increase of eastward geomagnetic ®eld (Y). It is shown that during the counter electrojet period when DH is negative, DY also becomes negative. Thus, the diurnal variation of DY at equatorial latitudes is suggested to be a constituent part of the equatorial electrojet current system. Solar ̄ares are known to increase the H ®eld at an equatorial station during normal electrojet conditions (nej). At Huancayo, situated north of the magnetic equator, the solar ̄are e€ect, during nej, consists of positive impulses in H and Y and negative impulse in Z ®eld. During counter electrojet periods (cej), a solar ̄are produces a negative impulse in H and Y and a positive impulse in Z at Huancayo. It is concluded that both the zonal and meridional components of the equatorial electrojet in American longitudes, as in Indian longitudes, ̄ows in the same, E region of the ionosphere.