Bibcode
Wiegelmann, T.; Yelles Chaouche, L.; Solanki, S. K.; Lagg, A.
Bibliographical reference
Astronomy and Astrophysics, Volume 511, id.A4
Advertised on:
2
2010
Journal
Citations
18
Refereed citations
18
Description
Context. Solar magnetic fields are regularly extrapolated into the
corona starting from photospheric magnetic measurements that can be
affected by significant uncertainty. Aims: We study how
inaccuracies introduced into the maps of the photospheric magnetic
vector by the inversion of ideal and noisy Stokes parameters influence
the extrapolation of nonlinear force-free magnetic fields.
Methods: We compute nonlinear force-free magnetic fields based on
simulated vector magnetograms, by the inversion of Stokes profiles that
were computed by a 3-D radiation MHD simulation snapshot. These
extrapolations are compared with extrapolations that originate directly
in the field in the MHD simulations, which is our reference. We
investigate how line formation and instrumental effects such as noise,
limited spatial resolution, and the effect of employing a filter
instrument influence the resulting magnetic field structure. The
comparison is performed qualitatively by visually inspecting the
magnetic field distribution and quantitatively by different metrics. Results: The reconstructed field is most accurate if ideal Stokes
data are inverted and becomes less accurate if instrumental effects and
noise are included. The results demonstrate that the nonlinear
force-free field extrapolation method tested here is relatively
insensitive to the effects of noise in measured polarization spectra at
levels consistent with present-day instruments. Conclusions: Our
results show that we can reconstruct the coronal magnetic field as a
nonlinear force-free field from realistic photospheric measurements with
an accuracy of a few percent, at least in the absence of sunspots.
Related projects
Numerical Simulation of Astrophysical Processes
Numerical simulation through complex computer codes has been a fundamental tool in physics and technology research for decades. The rapid growth of computing capabilities, coupled with significant advances in numerical mathematics, has made this branch of research accessible to medium-sized research centers, bridging the gap between theoretical and
Daniel Elías
Nóbrega Siverio