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Title: Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model

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 ARmore » 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.« less

Authors:
;  [1]; ;  [2];  [3]
  1. Physics Department, Center for Solar-Terrestrial Research, New Jersey Institute of Technology Newark, NJ, 07102-1982 (United States)
  2. Institute of Solar-Terrestrial Physics (ISZF), Lermontov st., 126a, Irkutsk, 664033 (Russian Federation)
  3. Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 (Russian Federation)
Publication Date:
OSTI Identifier:
22661156
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 839; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; BOUNDARY CONDITIONS; CHROMOSPHERE; COMPARATIVE EVALUATIONS; ERRORS; EXTRAPOLATION; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PHOTOSPHERE; SUN

Citation Formats

Fleishman, Gregory D., Loukitcheva, Maria, Anfinogentov, Sergey, Mysh’yakov, Ivan, and Stupishin, Alexey. Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA6840.
Fleishman, Gregory D., Loukitcheva, Maria, Anfinogentov, Sergey, Mysh’yakov, Ivan, & Stupishin, Alexey. Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model. United States. doi:10.3847/1538-4357/AA6840.
Fleishman, Gregory D., Loukitcheva, Maria, Anfinogentov, Sergey, Mysh’yakov, Ivan, and Stupishin, Alexey. Mon . "Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model". United States. doi:10.3847/1538-4357/AA6840.
@article{osti_22661156,
title = {Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model},
author = {Fleishman, Gregory D. and Loukitcheva, Maria and Anfinogentov, Sergey and Mysh’yakov, Ivan and Stupishin, Alexey},
abstractNote = {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.},
doi = {10.3847/1538-4357/AA6840},
journal = {Astrophysical Journal},
number = 1,
volume = 839,
place = {United States},
year = {Mon Apr 10 00:00:00 EDT 2017},
month = {Mon Apr 10 00:00:00 EDT 2017}
}