The effect of counter electrojet on the plasma distribution of the topside ionosphere

Evidence of strong correlation between the counter electrojet and the behaviour of the topside ionosphere is presented here. The reality of the counter electrojet is established by the magnetic field variations of the H-component and the bottom side ionograms at Huancayo. For the same event, the latitudinal plasma distributions of the topside ionosphere are studied. It is shown that the E-region electric field associated with the counter electrojet pushed the plasma downwards even on the topside as high as 600 km. The well known crest-trough formation is also shown to be absent on the counter electrojet day