Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model
Document Type
Article
Publication Date
4-10-2017
Abstract
Quantifying the coronal magnetic field remains a central problem in solar physics. Nowadays, the coronal magnetic field is often modeled using nonlinear force-free field (NLFFF) reconstructions, whose accuracy has not yet been comprehensively assessed. Here we perform a detailed casting of the NLFFF reconstruction tools, such as π-disambiguation, photospheric field preprocessing, and volume reconstruction methods, using a 3D snapshot of the publicly available full-fledged radiative MHD model. Specifically, from the MHD model, we know the magnetic field vector in the entire 3D domain, which enables us to perform a "voxel-by-voxel" comparison of the restored and the true magnetic fields in the 3D model volume. Our tests show that the available π-disambiguation methods often fail in the quiet-Sun areas dominated by small-scale magnetic elements, while they work well in the active region (AR) photosphere and (even better) chromosphere. The preprocessing of the photospheric magnetic field, although it does produce a more force-free boundary condition, also results in some effective "elevation" of the magnetic field components. This "elevation" height is different for the longitudinal and transverse components, which results in a systematic error in absolute heights in the reconstructed magnetic data cube. The extrapolations performed starting from the actual AR photospheric magnetogram are free from this systematic error, while other metrics are comparable with those for extrapolations from the preprocessed magnetograms. This finding favors the use of extrapolations from the original photospheric magnetogram without preprocessing. Our tests further suggest that extrapolations from a force-free chromospheric boundary produce measurably better results than those from a photospheric boundary.
Identifier
85017668398 (Scopus)
Publication Title
Astrophysical Journal
External Full Text Location
https://doi.org/10.3847/1538-4357/aa6840
e-ISSN
15384357
ISSN
0004637X
Issue
1
Volume
839
Grant
1312802
Fund Ref
Russian Academy of Sciences
Recommended Citation
Fleishman, Gregory D.; Anfinogentov, Sergey; Loukitcheva, Maria; Mysh'Yakov, Ivan; and Stupishin, Alexey, "Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model" (2017). Faculty Publications. 9632.
https://digitalcommons.njit.edu/fac_pubs/9632