WSO generates data about the Sun's magnetic field in the following forms:

  MAGNETOGRAMS

Magnetograms are magntic maps of the Sun's surface.  The Sun rotates every 27
days and the features change with time, so the maps change from day to day.

The GIF files show regions of strong positive and negative field as blue 
and red areas.

The Postscript files are contour maps of the magnetic field on the visible 
solar disk.  Dashed contours are negative.


  SYNOPTIC CHARTS

Synoptic Charts are magnetic maps of the whole Sun.  Magnetograms taken over a
solar rotation are combined to give a complete picture of the solar field.  The
Earth is near the solar equator, so we never get a very good look at the Sun's
poles.

The solar magnetic field postscript files are contour maps of the magnetic 
field for particular Carrington Rotations.  Carrington Rotations are a 
convenient coordinate system for locating positions on the sun.  The first 
Carrington Rotation was in 1853.  CR 1891 began on the last day of 1994.


  CORONAL FIELDS 

The field in the corona can not be measured directly.  However the field can be
modeled because it's basic structure is determined by the conditions in the
photosphere.  We use a potential field model to compute the field about 1.5
solar radii above the Sun's surface.  That's the height at which the field
pattern becomes fixed.  That pattern is carried out into interplanetary space
by the solar wind.  It takes about 4 days for the pattern to reach the Earth.
The model isn't very good at predicting dynamic changes in the corona.

The coronal synoptic charts are postscript contour plots of the magnetic
field at the source surface.

The "los" (line-of-sight) method has been used and published for many years; 
that model assumes that the field measured in the photosphere may be nonradial.
It requires a polar field correction that is observatory and temporally dependent.

The "rad" (radial) method is probably preferable. It assumes that the photospheric
field is radial in the photosphere. The method does not require a polar field
correction. The best source surface radius is 2.5, though 3.25 gave a little better
result when comparing with high latitude Ulysses measurements in 1994. During the extended
minimum at the end of Cycle 24 the source surface was probably best set even lower.


  HARMONIC COEFFICIENTS

The photospheric and coronal field can be decomposed into spherical harmonics.
The monopole, dipole, quadrupole, etc. components can be used to reconstruct
the field at any height between the photosphere and source surface.  There are
no plots, but you can get the coefficients in tables.  The harmonics computed
using the two models described above are slightly different.