Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.

M.A. Knyazeva, А.А. Namgaladze hemisphere, the winter ones - in the southern hemisphere, respectively). Their formation is caused by corresponding longitudinal variation of the meridional neutral wind at the altitudes o f the ionospheric F2-layer and geomagnetic field line geometry [Knyazeva, 2009]. The equatorial sides o f the EEDR’s abut on the equatorial anomaly remains in the night-time MLT sector. In the winter hemisphere the anomaly remains are clearly visible in the results o f the IRI-2001 and all UAM calculations. The equatorial anomaly and EEDR’s are separated by the through. In the summer hemisphere the equatorial “sides” o f the EEDR’s lie on the equatorial anomaly remains. As result these regions and equatorial anomaly are not separated. This effect takes place in summer solstice conditions under the high solar activity also. The seasonal variations of the equatorial anomaly and EEDR’s spatial structure at low latitudes are related to the corresponding variations of the dynamo origin zonal electric field (in Fig. 3, third row of the maps). The anomaly crests are clearly visible in winter (in all UAM versions) and summer conditions (by the UAM-MSIS and UAM- MSIS-HWM) in that hours by MLT, when the zonal electric field is eastward at low latitudes. The ionospheric plasma drifts under the action of this field to higher altitudes thus decreasing the ion loss rate. Accumulated plasma flows downward along the geomagnetic force lines and forms the equatorial anomaly crests. Conclusions Thus our investigation shows that the magnetospheric and thermospheric (dynamo) origin electric fields influence on the latitudinal location and form of the EEDR’s equatorial sides abutting on the equatorial anomaly remains in the night-time MLT sector. 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