Effect of Ionization Transport on the Equatorial F -Region

WE were interested to read the communication of Moffett and Hanson 1 describing calculations of electron density distributions in the equatorial F -region of the ionosphere. Following our earlier work 2 , which treated the effect of electromagnetic drift as a perturbation only, we have also carried out calculations including a drift of arbitrary magnitude, in exactly the same way as Moffett and Hanson. Our results, which will be described in detail elsewhere, are almost identical to theirs, differing only in slight variations of the parameters. They show the main features of the daytime equatorial anomaly, including the approximate field-alignment, in the topside ionosphere only, of the latitudinal maxima of electron density at fixed heights.