Role of lower thermospheric neutral concentration and F2-Region Ion drifts in the peak electron densities

Abstract

Data of three simultaneously measured ionospheric parameters, namely, the ion-neutral collision frequency (v_in) in the lower thermosphere, and ion drift (<i>V</i>_z) and electron concentration (<i>N</i>_e) in the F2 region, taken from the incoherent scatter radar measurements at Arecibo (lat. 18.3°N; long. 66.7°W) for the period Aug. 1974-May 1977, have been analyzed. The analysis shows that the variability in peak electron density (<i>N_m</i>) cannot be explained on the basis of changes in the F-region vertical ion drift alone. Changes in neutral concentration, which are seen in the ion-neutral collision frequency in the lower thermosphere, need also be considered.