Observing the Magnetic Sun
Magnetographs
-
Tiny detectors that measure the Zeeman Effect on the photosphere
-
Filters are used to produce an image in each direction of
circular polarization
-
The difference of these images yields the longitudinal component
of the magnetic field on the photosphere (the component in and out of the
sun)
Vector Magnetographs
-
Measures the direction and degree of linear polarization
and circular polarization
-
Once again, from the circular polarization one finds the
longitudinal component of the magnetic field
-
Analyzing the linear polarization, the strength and direction
of the transverse field is mapped (the field on the plane of the sun)
This results in a 3D description of the magnetic field on
the photosphere, which can be extrapolated into the corona for comparison
with coronal magnetic data
From the bottom left clockwise we see magnetograph data
of the transverse magnetic field, the continuum, and the line of sight
magnetic field.