Equatorial Ionization Anomaly (EIA) under the Solar Radiation Spectrum

Abstract

This article aims to provide an answer to the equatorial or geomagnetic anomaly solely from the spectrum or power of solar radiation. Thus, each latitude at the level of the ionosphere would have a quasi-constant power around which the fluctuations in the power of solar radiation occur. Its quasi-constancy would be due to the fact that its amplitude fluctuations would be very negligible compared to those of the power of solar radiation so as not to break its sinusoidal shape and while allowing the resolution of the geomagnetic anomaly. This power of solar radiation dependent on latitude is a sinusoid with on the one hand maxima observed at 13˚ North latitude and 13˚ South latitude and on the other hand a minimum centered at the magnetic equator of latitude 0˚. Such a sinusoidal shape allows justifying the dome structure for the HmF2 altitudes and the gutter structure for the NmF2 ion density centered on the magnetic equator in magnetically calm periods of both foF2 and TEC. However, by taking into account these fluctuations and considering that the latitudinal powers observed in the Northern hemisphere are in “advance” of phase on those in the Southern hemisphere, the other characteristics of the equatorial anomaly in magnetically disturbed periods find answers. Such as the general symmetry of the crests when the latitudinal powers in the North are equal to those in the South, the asymmetry when in the North they are different from those in the South and finally the inverse fountain effect when the latitudinal powers at the equator or those close to the equator tend to prevail or prevail over the latitudinal powers in the North and South located at the latitudes of maximum density or very close to them. Finally, hourly and monthly ranges of symmetries and asymmetries, of tightening of the anomaly or of the equator effect have been identified, thus allowing better navigation and better performance of telecommunications tools.