An optimization principle for computing stationary MHD equilibria with solar wind flow

Knowledge about the magnetic field and plasma environment is important
for almost all physical processes in the solar atmosphere. Precise
measurements of the magnetic field vector are done routinely only in
the photosphere, e.g. by SDO/HMI. These measurements are used as
boundary condition for modelling the solar chromosphere and corona,
whereas some model assumptions have to be made. In the low-plasma-beta
corona the Lorentz-force vanishes and the magnetic field
is reconstructed with a nonlinear force-free model. In the mixed-beta
chromosphere plasma forces have to be taken into account with the
help of a magnetostatic model. And finally for modelling the global
corona far beyond the source surface the solar wind flow has to
be incorporated within a stationary MHD model.
To do so, we generalize a nonlinear force-free and magneto-static optimization
code by the inclusion of a field aligned compressible plasma flow.
Applications are the implementation of the solar wind on
global scale. This allows to reconstruct the coronal magnetic field further
outwards than with potential field, nonlinear force-free and magneto-static models.
This way the model might help in future to provide the magnetic connectivity
for joint observations of remote sensing and in-situ instruments on Solar
Orbiter and Parker Solar Probe.