Mechanisms of longitudinal effect in the night-time equatorial anomaly of electron density in the outer ionosphere

Analysis of the ionosphere outer probing data, obtained by means of the Interkosmos-19 satellite for both solstices during high solar activity, has shown, that the most probable reasons for longitudinal effect in the equatorial anomaly are the neutral wind contribution prevails and is determined by wind zonal component action due to geomagnetic inclination longitudinal variations and meridional component effect due to essential dependence of its amplitude on latitude. The drift effect is connected with the longitudinal changes in geomagnetic field size over the equator. As the wind effect prevails, it leads to the seasonal dependence of the longitudinal effect character, which is essentially strong over the geomagnetic equator