Plasmaspheric extension of topside electron density profiles Original Research Article

Topside electron density profiles measured onboard ISIS-1 and ISIS-2 (1969 to 1980) and IK—19 (1979 to 1982) are extended through the plasmasphere using Chasovitinʹs (1999) model describing the plasma density between the peak of the ionosphere and the plasmapause. The altitude of the plasmapause hpl, varying from ∼6,000 km to ∼30,000 km, and plasmapause density Npl depend on geographic longitude and magnetic latitude, the solar activity, and modified geomagnetic index Kpm. It is found that the plasmasphere fraction of the total electron content TEC calculated with extended ISIS1,2 and IK19 profiles including IRI bottomside profile comprises 20 to 50% of the ionospheric electron content in most cases.