Geomagnetic Distortion of the F2 Region on the Magnetic Equator

Abstract

The direct relation between the geomagnetic S_q variation and the vertical electron drift in the F2 region on the magnetic equator is examined. It is shown that the electric field in the F2 region accompanied by S_q electric current produces the vertical drift which is sufficient to interpret the main features of the anomaly of the F2 region on the equator. It is to be noticed that the main term of the drift velocity is diurnal. The daily variations of the maximum electron density and its height in the F2 region are calculated under consideration of the vertical electron drift for the reasonable distribution of decay coefficient with altitude inferred by observed results. The calculated F2 daily variations have a striking resemblance with those observed near the magnetic equator. When the ion production takes its maximum value at about 200km, there appears a lower secondary maximum of electron density which agrees well with the observed F1 layer. The change of characteristics of daily variations of the F2 region with the sunspot-cycle is likely to be accounted for by a slight shift of the phase of the drift.