Nonlinear force-free coronal magnetic field modelling and preprocessing of vector magnetograms in spherical geometry
From MaRDI portal
Publication:3551081
DOI10.1051/0004-6361/200912529zbMATH Open1183.85013arXiv0912.1514OpenAlexW2006362340WikidataQ68859578 ScholiaQ68859578MaRDI QIDQ3551081
Author name not available (Why is that?)
Publication date: 8 April 2010
Published in: (Search for Journal in Brave)
Abstract: Context: Knowledge about the coronal magnetic field is important to the understanding the structure of the solar corona. We compute the field in the higher layers of the solar atmosphere from the measured photospheric field under the assumption that the corona is force-free. Aims: Here we develop a method for nonlinear force-free coronal magnetic field medelling and preprocessing of photospheric vector magnetograms in spherical geometry using the optimization procedure. Methods: We describe a newly developed code for the extrapolation of nonlinear force-free coronal magnetic fields in spherical coordinates over a restricted area of the Sun. The program uses measured vector magnetograms on the solar photosphere as input and solves the force-free equations in the solar corona. We develop a preprocessing procedure in spherical geometry to drive the observed non-force-free data towards suitable boundary conditions for a force-free extrapolation. Results: We test the code with the help of a semi-analytic solution and assess the quality of our reconstruction qualitatively by magnetic field line plots and quantitatively with a number of comparison metrics for different boundary conditions. The reconstructed fields from the lower boundary data with the weighting function are in good agreement with the original reference fields. We added artificial noise to the boundary conditions and tested the code with and without preprocessing. The preprocessing recovered all main structures of the magnetogram and removed small-scale noise. The main test was to extrapolate from the noisy photospheric vector magnetogram with and without preprocessing. The preprocessing was found to significantly improve the agreement between the extrapolated and the exact field.
Full work available at URL: https://arxiv.org/abs/0912.1514
No records found.
No records found.
This page was built for publication: Nonlinear force-free coronal magnetic field modelling and preprocessing of vector magnetograms in spherical geometry
Report a bug (only for logged in users!)Click here to report a bug for this page (MaRDI item Q3551081)
