Modeling the F2 Topside and Plasmasphere for IRI

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


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
most/all 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. While the Chapman (neutral)
scale-height H(h) varies only slowly near hmF2, it increases rapidly at the O+
to light-ion transition height. A hyperbolic tangent function is suitably
representing 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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Fall Meeting, American Geophysical Union, San Francisco, U.S.A., 2005