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Title: Comparison of Two Coronal Magnetic Field Models to Reconstruct a Sigmoidal Solar Active Region with Coronal Loops

Abstract

Magnetic field extrapolation is an important tool to study the three-dimensional (3D) solar coronal magnetic field, which is difficult to directly measure. Various analytic models and numerical codes exist, but their results often drastically differ. Thus, a critical comparison of the modeled magnetic field lines with the observed coronal loops is strongly required to establish the credibility of the model. Here we compare two different non-potential extrapolation codes, a nonlinear force-free field code (CESE–MHD–NLFFF) and a non-force-free field (NFFF) code, in modeling a solar active region (AR) that has a sigmoidal configuration just before a major flare erupted from the region. A 2D coronal-loop tracing and fitting method is employed to study the 3D misalignment angles between the extrapolated magnetic field lines and the EUV loops as imaged by SDO /AIA. It is found that the CESE–MHD–NLFFF code with preprocessed magnetogram performs the best, outputting a field that matches the coronal loops in the AR core imaged in AIA 94 Å with a misalignment angle of ∼10°. This suggests that the CESE–MHD–NLFFF code, even without using the information of the coronal loops in constraining the magnetic field, performs as good as some coronal-loop forward-fitting models. For the loops as imagedmore » by AIA 171 Å in the outskirts of the AR, all the codes including the potential field give comparable results of the mean misalignment angle (∼30°). Thus, further improvement of the codes is needed for a better reconstruction of the long loops enveloping the core region.« less

Authors:
;  [1];  [2]; ; ;  [3];  [4]
  1. Key Laboratory of Computational Geodynamics, University of Chinese Academy of Sciences, Beijing 100049 (China)
  2. Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen, 518055 (China)
  3. Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
  4. School of Space and Environment, Beihang University, Beijing 100191 (China)
Publication Date:
OSTI Identifier:
22663470
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 842; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CONFIGURATION; EXTRAPOLATION; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; NONLINEAR PROBLEMS; SOLAR CORONA; SUN; THREE-DIMENSIONAL CALCULATIONS

Citation Formats

Duan, Aiying, Zhang, Huai, Jiang, Chaowei, Hu, Qiang, Gary, G. Allen, Wu, S. T., and Cao, Jinbin, E-mail: duanaiying@ucas.ac.cn, E-mail: hzhang@ucas.ac.cn, E-mail: chaowei@hit.edu.cn. Comparison of Two Coronal Magnetic Field Models to Reconstruct a Sigmoidal Solar Active Region with Coronal Loops. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA76E1.
Duan, Aiying, Zhang, Huai, Jiang, Chaowei, Hu, Qiang, Gary, G. Allen, Wu, S. T., & Cao, Jinbin, E-mail: duanaiying@ucas.ac.cn, E-mail: hzhang@ucas.ac.cn, E-mail: chaowei@hit.edu.cn. Comparison of Two Coronal Magnetic Field Models to Reconstruct a Sigmoidal Solar Active Region with Coronal Loops. United States. doi:10.3847/1538-4357/AA76E1.
Duan, Aiying, Zhang, Huai, Jiang, Chaowei, Hu, Qiang, Gary, G. Allen, Wu, S. T., and Cao, Jinbin, E-mail: duanaiying@ucas.ac.cn, E-mail: hzhang@ucas.ac.cn, E-mail: chaowei@hit.edu.cn. Tue . "Comparison of Two Coronal Magnetic Field Models to Reconstruct a Sigmoidal Solar Active Region with Coronal Loops". United States. doi:10.3847/1538-4357/AA76E1.
@article{osti_22663470,
title = {Comparison of Two Coronal Magnetic Field Models to Reconstruct a Sigmoidal Solar Active Region with Coronal Loops},
author = {Duan, Aiying and Zhang, Huai and Jiang, Chaowei and Hu, Qiang and Gary, G. Allen and Wu, S. T. and Cao, Jinbin, E-mail: duanaiying@ucas.ac.cn, E-mail: hzhang@ucas.ac.cn, E-mail: chaowei@hit.edu.cn},
abstractNote = {Magnetic field extrapolation is an important tool to study the three-dimensional (3D) solar coronal magnetic field, which is difficult to directly measure. Various analytic models and numerical codes exist, but their results often drastically differ. Thus, a critical comparison of the modeled magnetic field lines with the observed coronal loops is strongly required to establish the credibility of the model. Here we compare two different non-potential extrapolation codes, a nonlinear force-free field code (CESE–MHD–NLFFF) and a non-force-free field (NFFF) code, in modeling a solar active region (AR) that has a sigmoidal configuration just before a major flare erupted from the region. A 2D coronal-loop tracing and fitting method is employed to study the 3D misalignment angles between the extrapolated magnetic field lines and the EUV loops as imaged by SDO /AIA. It is found that the CESE–MHD–NLFFF code with preprocessed magnetogram performs the best, outputting a field that matches the coronal loops in the AR core imaged in AIA 94 Å with a misalignment angle of ∼10°. This suggests that the CESE–MHD–NLFFF code, even without using the information of the coronal loops in constraining the magnetic field, performs as good as some coronal-loop forward-fitting models. For the loops as imaged by AIA 171 Å in the outskirts of the AR, all the codes including the potential field give comparable results of the mean misalignment angle (∼30°). Thus, further improvement of the codes is needed for a better reconstruction of the long loops enveloping the core region.},
doi = {10.3847/1538-4357/AA76E1},
journal = {Astrophysical Journal},
number = 2,
volume = 842,
place = {United States},
year = {Tue Jun 20 00:00:00 EDT 2017},
month = {Tue Jun 20 00:00:00 EDT 2017}
}