Comparison of analytical functions used to describe topside electron density profiles with satellite data

Electron density models of the ionosphere use different analytical formulations for the electron density vertical profile in the topside. The present paper compares some single-layer topside analytical descriptions (Chapman, Epstein, modified Epstein used in the NeQuick model) with experimental topside profiles obtained from measurements of IK19 and ISIS2 satellites. The limits of height range and shape for each formulation are described and analyzed and suggestions for the use of multiple layers solution to reproduce experimental results are given.