Night-time F-region and daytime E-region ionospheric drifts measured at Udaipur during solar flares

Abstract

Abstract. Ionospheric drifts measured at a low latitude station, Udaipur (Geomag. Lat. 14.5 • N), in the night-time Fregion and daytime E-region during solar flares have been studied. The night-time observations, which correspond to the F-region drifts, were carried out on five different nights. The daytime observation corresponding to the E-region drifts is only for one day. It is found that the apparent drift during the solar flare period is reduced considerably, in the daytime E-region as well as in the night-time F-region. The East-West and North-South components of the apparent drift speed are also similarly affected. For the daytime E-region drifts during a flare, increased ionization and subsequent reduction of reflection height is proposed to be the cause of reduced drift speeds. For the night-time F-region drifts, a reduced electric field at the F-region heights resulting from coupling of sunlit and dark hemispheres has been proposed to be the possible cause.

Influence of Geomagnetic Storms On VHFIonospheric ScintillationsAtNear Equatorial Station Anantapur

“…Geomagnetic storms of the second type namely the Gradual Commencement type show no clear indication of the onset and hence they are called gradual commencement storms which are characterized by the main phase only. Two types of disturbance fields, the field caused by the compression of the magnetosphere and the field produced by the ring current characterize these storms [9,10]. The variability observed in the development of geomagnetic storms can be interpreted as due to a combination of these two fields in different ratios.…”