NASA/GSFC, Code 695

Greenbelt, Maryland 20771

NSI-DECnet: LEPVAX::U2DHF

**Brief Description**:

For this tilt dependent model, four sets of model coefficients are available
for four levels of magnetic activity as parameterized by Kp. It is valid out to
17 Earth radii. The model is expressed as second order power series expansions
in solar magnetic coordinates, quadratic in position and linear in tilt. Model
coefficients (17) were obtained by a least-square-fit to 12,616 vector field
measurements from 451 orbits of four IMP satellites between 1966 and 1972. The
effect of localized current systems like the ring current and sheet currents in
the tail are not particularly well modeled by these quadratic expansions. The
program includes the GSFC(12/66) main field model for
the representation of the internal (core) part of Earth's total magnetic field.
A simple offset dipole field can be chosen instead of the spherical harmonics
GSFC model, to reduce the computation time.

**References**:

D. H. Fairfield and G. D. Mead, Magnetospheric Mapping with a Quantitative
Geomagnetic Field Model, J. Geophys. Res. 80, 535, 1975.

Go to the Model Web Models home page