Bibcode
Wiegelmann, T.; Solanki, S. K.; Yelles, L.; Lagg, A.
Bibliographical reference
Proceedings of The Second Solar Orbiter Workshop, by Marsch, E.; Tsinganos, K.; Marsden, R.; Conroy, L. ESA-SP 641. ISBN: 92-9291-205-2. Noordwijk, Netherlands: European Space Agency, 2006, id.19
Advertised on:
10
2006
Citations
0
Refereed citations
0
Description
The aim of this work is to investigate how photon noise and errors in
the retrieval of solar magnetic parameters from measured Stokes profiles
influences the extrapolartion of nonlinear force-free coronal magnetic
fields from photospheric vector magnetograms. To do so we use a
nonlinear force-free extrapolation code based on an optimization
principle. The extrapolation methods has been extensively tested and
applied to data from various telescopes. Here we apply the code
artificial vector magnetograms obtained from 3-D radiation-MHD
simulations. As a reference case we compute the coronal magnetic field
from an ideal magnetogram and compare the result with more realistic
magnetograms based on simulated Solar Orbiter/VIM-measurements. We
investigate the effect of noise, ambiguities, spatial resolution,
inversion mechanism, of Stokes profiles etc. We rate the quality of the
reconstructed coronal magnetic field qualitatively by magnetic field
line plots and quantitatively by a number of comparison metrices, e.g.,
the vector correlation with the exact solution and how accurate the free
magnetic energy is computed. Not surprisingly, the instrument effects
and noise influence the quality of the nonlinear force-free coronal
magnetic field model. The extrapolations from realistic vector
magnetograms show a reasonable agreement with the ideal reconstruction,
however, and are in particular significantly better than extrapolations
based on line-of-sight magnetograms only. High quality VIM data will
thus allow reasonably accurate extrapolations that can serve as the
basis for magnetic coupling science through a comparison with
observations from EUS and EUI.