Observations by incoherent scatter radar of related D- and F-region structuring at very high latitude

Abstract

Properties and associations of F- and D-region ionospheric structures during weak electron precipitation at very high latitude are investigated using the Longyearbyen incoherent scatter radar. The radio absorption deduced from the electron density observations revealed evidence of a persistent low-altitude absorption layer peaking at 80-85 km. Inversion of the electron density profile to give an estimate of the incoming energetic electron spectrum suggests that its source may be the solar wind. Strong similarities are seen between variations in the F and D regions which suggest that the electron flux reaching the D-region is being modulated in energy by the variations of electron density in the F-region.