EXTRAPOLATION OF THE SOLAR CORONAL MAGNETIC FIELD FROM SDO /HMI MAGNETOGRAM BY A CESE-MHD-NLFFF CODE

Due to the absence of direct measurement, the magnetic field in the solar corona is usually extrapolated from the photosphere in a numerical way. At the moment, the nonlinear force-free field (NLFFF) model dominates the physical models for field extrapolation in the low corona. Recently, we have dev...

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Bibliographic Details
Published in:The Astrophysical journal 2013-06, Vol.769 (2), p.1-13
Main Authors: Jiang, Chaowei, Feng, Xueshang
Format: Article
Language:English
Subjects:
Assessments
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Coronas
ERUPTION
EXTRAPOLATION
FILAMENTS
Flares
LIMITING VALUES
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
Mathematical models
NOAA
NOISE
PHOTOSPHERE
RELAXATION
SOLAR CORONA
Solar observatories
SPACE-TIME
SUN
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Summary:Due to the absence of direct measurement, the magnetic field in the solar corona is usually extrapolated from the photosphere in a numerical way. At the moment, the nonlinear force-free field (NLFFF) model dominates the physical models for field extrapolation in the low corona. Recently, we have developed a new NLFFF model with MHD relaxation to reconstruct the coronal magnetic field. This method is based on CESE-MHD model with the conservation-element/solution-element (CESE) spacetime scheme. In this paper, we report the application of the CESE-MHD-NLFFF code to Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) data with magnetograms sampled for two active regions (ARs), NOAA AR 11158 and 11283, both of which were very non-potential, producing X-class flares and eruptions. The raw magnetograms are preprocessed to remove the force and then inputted into the extrapolation code. Qualitative comparison of the results with the SDO/AIA images shows that our code can reconstruct magnetic field lines resembling the EUV-observed coronal loops. Most important structures of the ARs are reproduced excellently, like the highly sheared field lines that suspend filaments in AR 11158 and twisted flux rope which corresponds to a sigmoid in AR 11283. Quantitative assessment of the results shows that the force-free constraint is fulfilled very well in the strong-field regions but apparently not that well in the weak-field regions because of data noise and numerical errors in the small currents.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/769/2/144