Magnetic Field Data File

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The Magnetic Field Data files contains the Gaussian coefficients used in the spherical harmonic expansion of the Earth’s magnetic field vector. The empirically determined coefficients are updated every five years.

 

The IGRF.dat file, used by default, is the current generation of the International Geomagnetic Reference Field model obtained from the NOAA National Geophysical Data Center website. Recent generations of the model are included as well.

 

The IGRF1960, IGRF1965, and IGRF1970 files are used for computing particle fluxes in the Spacecraft.ParticleFlux and Spacecraft.ParticleFluxTimes methods.

 

A portion of a Magnetic Field data file is shown below. The first line in the file is the epoch of the coefficients. In this example, the coefficients are from the IGRF 2014 model and the epoch is 1/1/2014. The second line in the file is the order of the spherical harmonic expansion. The remaining lines are the G & H coefficients and their time derivatives.
 

FieldEpoch = 01 Jan 2014 12:00:00.000

FieldOrder = 13

G[ 0 ][ 0 ] =      0.0

G[ 1 ][ 0 ] = -29442.0

G[ 1 ][ 1 ] =  -1501.0

G[ 2 ][ 0 ] =  -2445.1

G[ 2 ][ 1 ] =   3012.9

G[ 2 ][ 2 ] =   1676.7

...

Gt[ 0 ][ 0 ] =     0.0

Gt[ 1 ][ 0 ] =    10.3

Gt[ 1 ][ 1 ] =    18.1

Gt[ 2 ][ 0 ] =    -8.7

Gt[ 2 ][ 1 ] =    -3.3

Gt[ 2 ][ 2 ] =     2.1

...

H[ 0 ][ 0 ] =      0.0

H[ 1 ][ 0 ] =      0.0

H[ 1 ][ 1 ] =   4797.1

H[ 2 ][ 0 ] =      0.0

H[ 2 ][ 1 ] =  -2845.6

H[ 2 ][ 2 ] =   -641.9

...

Ht[ 0 ][ 0 ] =     0.0

Ht[ 1 ][ 0 ] =     0.0

Ht[ 1 ][ 1 ] =   -26.6

Ht[ 2 ][ 0 ] =     0.0

Ht[ 2 ][ 1 ] =   -27.4

Ht[ 2 ][ 2 ] =   -14.1