Post-Sunset Uplifting of the Equatorial F Layer of the Ionosphere and Vertical Plasma Drift Velocities.

Abstract

The paper describes the comparison of individual measurements of the vertical plasma drift velocities in the F region of the ionosphere, VzF, computed from the doppler shift of 50MHz backscatter echoes at Jicamarca, Peru during the post-sunset hours with the corresponding values of the vertical velocity of the F layer computed from the rate of change of the minimum virtual height of the F layer, ∂h′minF/∂t, at Huancayo, Peru.It is found that there is a remarkable coincidence in the time of the reversal of vertical drift velocities of plasma measured by VHF incoherent radar and the F region vertical drift computed from the HF ionosonde. Statistically, the F layer vertical drift from ionogram data is about two-third of the incoherent scatter radar plasma drift velocities.Such a calibration would be greatly useful to study electric fields during sunset hours in the equatorial ionosphere at different longitudes where long series of ionospheric data are available.