Magnetic fields within the Earth system, and throughout the planets,
provide a strong organizing force for processes active both within a
planet or moon, and outside of it
(Nicholas et al, 2011).
In the interest of stimulating research and education in the field of
comparative planetology and geomagnetism, we present interactive
applications that allow the user to evaluate magnetic fields for
planets and satellites that host internal magnetic fields.
We also make available Fortran source codes and the models themselves.
We expect that by the time of this Fall's AGU in December these codes
will be documented, will be enhanced to include Matlab codes (courtesy
of C. Johnson and N. Olsen), and have benchmarks.
Models are included for Earth
(Comprehensive model CM4 of
Sabaka et al., 2004, Geophysics J. Int.),
Mercury
(Anderson et al., 2011, Science),
the Moon
(Purucker and Nicholas, 2010, JGR),
Mars
(Langlais et al., 2004, JGR;
Lillis et al., 2010, JGR),
and the outer planets Jupiter, Saturn, Uranus, and Neptune
(Russell and Dougherty, 2010, Space Science Reviews;
Holme and Bloxham, 1996, JGR).
The predictive MoSST (Kuang and Tangborn, 2011) model for the Earth's
magnetic field will also be included within the next few weeks.
All models include magnetic fields of internal origin, and fields of
external origin are included in the models for the Earth.
By the time of AGU we expect to include models with external fields for
Mercury and the Moon.
As models evolve, we intend to include magnetic fields of external
origin for the other planets and moons.
At the moment all calculations are in a body-fixed coordinate system
centered in the planetary object.
In the future, this website will allow the user to select a coordinate
system, such as planet-centered, heliocentric, or boundary normal.
At present, the user provides the location within the body-fixed
coordinate system, and the vector magnetic field due to each of the
component source fields at that location is then calculated and
presented.
Alternatively, the user can input a range as well as a grid spacing,
and the vector magnetic field will be calculated for all points on that
grid and be made available as a file for downloading.
The Fortran source codes rely in part on the
SHTOOLS package of Mark Wieczorek.
