Availability: FORTRAN code may be available from the (see model authors)
The Fully Analytical Ionospheric Model (FAIM) uses the formalism of the Chiu model with coefficients fitted to the SLIM model profiles. The local time variation is expressed by a Fourier series up to order 6 and the variation with dip latitude by a fourth order harmonic oscillator function (Hermite polynomial).
D. N. Anderson, J. M. Forbes, and M. Codrescu, A Fully Analytical, Low- and Middle-Latitude Ionospheric Model, J. Geophys. Res. 94, 1520, 1989.
J. M. Forbes, N. N. Anderson, M. Codrescu, and P. P. Batista, An Analytical/Empirical Model of the Middle and Low Latitude Ionosphere, Air Force Geophysics Laboratory, Report GL-TR-89- 0096, Hanscom AFB, Massachusetts, 1989.