If you have more questions regarding the Earth's magnetosphere and geomagnetism,
or would like to refresh your memory of even more general topics, covering basic
astronomy and space physics, here is an extensive
educational web resource, developed by David Stern.
Online resources for the geomagnetic field modeling
Geophysical coordinate systems
In geophysics and space physics, individual phenomena or objects can be most
conveniently described in different coordinate systems that take into account
their specific properties in the most natural and simplest way. For example, the
main geomagnetic field is rigidly tied to rotating Earth and, hence, can be best
described in geocentric geographic (GEO) or dipole magnetic (MAG) coordinates.
There exist several coordinate systems most often used in studies of the geomagnetic
field and Sun-Earth connections; a detailed overview of those systems can be found in
papers by Russell [Cosmic Electrodyn., v.2, pp. 184-196, 1971], Hapgood
[Planet. Space Sci., v.40(5), pp. 711-717, 1992; Ann. Geophys., v.13,
pp. 713-716, 1995]; there also exist comprehensive online resources, such as
This website offers a set of FORTRAN subroutines for transformations between various
geophysical coordinate systems.
The most recent revised and extended version (update of Dec.01, 2010)
of the package GEOPACK-2008 is now available.
IGRF-11 model coefficients are now added, extending the time span of the main field model through 2015.
The package includes 20 subroutines for evaluating field vectors, tracing field
lines, transformations between various coordinate systems, and locating the magnetopause position. A new feature,
not available in previous releases, is the possibility to take into account the observed direction of the solar wind,
which not only aberrates by ~4 degrees from the strictly radial Sun-Earth line, but also often significantly
fluctuates around that average direction.
Full documentation file: (Word, 180 KB)
Double-precision version: (GEOPACK-2008_dp)
ATTENTION: see ERRATA for recent corrections/updates (last correction of
Geopack-2008 made on November 30, 2010)
Two examples of a typical FORTRAN program, using
the GEOPACK-2008 routines for the field line tracing
Licensing information: All programs/codes presented on this site is free software: you can download,
redistribute and/or modify it under the terms of the GNU General
Public License as published by the Free Software Foundation, either version 3 of the License,
or any later version.
A copy of the GNU General Public License can also be found at
GNU website .
Magnetospheric magnetic field models
The data-based approach to the modeling of the geomagnetosphere has been developed over
the last 3 decades, starting with the pioneering work by Mead and Fairfield .
Subsequent efforts [Tsyganenko and Usmanov, 1982; Tsyganenko, 1987, 1989, 1996, 2002, 2003, 2005] resulted
in more refined models, used since then in many studies. The principal goal of the data-based magnetosphere
modeling is to extract full information from large sets of available data
, bridge the gap between theory and observations, and help answer a fundamental
question "What is the actual
structure of the geospace magnetic field and how is it related to changing interplanetary
conditions and the ground disturbance level?"
Links below can be used for downloading FORTRAN source codes of data-based models, developed
by the author of this web resource during the last 25 years.
- A source code for the TS05 (aka TS04), a dynamical empirical
model of the inner storm-time magnetosphere. Click here
for a detailed description of the model.
Yearly input data files (1995-2010) and related documentation for the TS05 model .
- Click here to download a source code (Fortran-77)
of the T02 (aka T01_01) model of the inner and near magnetosphere. Publications:
Paper I and
See ERRATA for a list of recent corrections/updates
(last correction of T02 and TS05: June 24, 2006).
- Click here to download a source code (Fortran-77) of the
T96 model. More detailed information on the model: Paper I
and Paper II.
- Click here if you need a source code of the
1989 model (T89c).
- Click here to view the list of data sets
used in the derivation of the models.
Click on highlighted items below for latest developments:
Magnetospheric configurations from a high-resolution data-based magnetic field model (abstract)
(JGR-A, v.112(A6), 2007) (PDF 2.3MB).
Dynamical data-based modeling of the storm-time geomagnetic field with enhanced
spatial resolution (abstract)
(Published in JGR-A, July 30, 2008) (PDF ~21.0MB).
Note: The two papers cited above present main ideas and first results obtained
using a new approach to the data-based modeling. Its essence boils down to
(1) employing extensible high-resolution expansions for the field of equatorial
currents and (2) a special data mining technique based on a "nearest-neighbor"
search in the parameter space. More details on the advanced modeling methods
and results can be found on our companion site, maintained by Mikhail Sitnov
Magnetic field and electric currents in the vicinity of polar cusps
as inferred from Polar and Cluster data (abstract)
(Published in Annales Geophysicae, April 2, 2009) (PDF ~3.0MB).
On the reconstruction of magnetospheric plasma pressure distributions
from empirical geomagnetic field models (abstract)
(Published in JGR-A, July 15, 2010) (Full article, PDF ~1.2MB).
Author and curator:
Dr. Nikolai Tsyganenko
Department of Earth's Physics, Institute of Physics, University of St.-Petersburg,
Petrodvoretz, St.-Petersburg 198504, Russian Federation
This site was started on February 15, 2008
The most recent update: March 11, 2011 (a SAVE statement was added in the source code of the T96 model,
to avoid run-time problems with Intel Fortran compilers).
Dec 8, 2010 (TS05 model parameters for Jan 1 - Nov 7, 2010 added);
December 1, 2010 (Earth's main field model extended by adding IGRF-11 coefficients
in the Geopack-2008 s/w;
March 13, 2010 (licensing info added);
February 25, 2010; June 11, 2009; March 3, 2009; April 21 and July 31, 2008.