Use a Fourier transform with the photospheric data as
a boundary condition to compute the three dimensional magnetic configuration
of the active region. We must assume alpha is constant and create
a linear force-free field.
Definition of the three magnetic field components for the Fourier Transform
(Bi is the magnetic field in the 3D volume)
,
,
Fourier
transform of Bz on the photosphere (I know this value)
The Fourier components of the magnetic field depend only on bz0
Potential Field
I made this 3D plot of the potential field using software
developed by S. Regnier. The base layer topographically maps the strength
of Bz on the photosphere with positive areas in red and negative areas
in blue. Coronal magnetic field lines loop out above the photosphere.