Modeling the F2 Topside and Plasmasphere for IRI

B. W Reinisch, P. Nsumei, X. Huang, and D. K. Bilitza


Empirical models are an important tool for the study of the different geospace
regions from Earth to sun, providing the user with easy access to a synthesis of
reliable measurements from ground and space specific parameters and regions.
This paper describes a new effort to develop a coherent model of the topside F2
layer and the plasmasphere with the goal to improve the representation of the
topside electron density in the IRI model and to extend the IRI description into
the plasmasphere. An _-Chapman function with a continuously varying
scale-height, dubbed a vari-Chap function, is used to describe the topside F2
vertical electron density profile N(h) that seamlessly connects the ionosphere
with the plasmasphere. The Chapman (neutral) scale-height H(h) varies only
slowly near hmF2 and increases rapidly at the O+ to light-ion transition height.
A hyperbolic tangent function suitably represents this variation. New
plasmasphere density profile data from the IMAGE/RPI measurements and topside
profiles from the ISIS topside sounders are used to construct a continuous
profile from hmF2 to several RE altitude.

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EGU meeting, Vienna Austria, April 2006