3-D nonlinear force-free field reconstruction of solar active region 11158 by direct boundary integral equation

Abstract

A 3-D coronal magnetic field is reconstructed for NOAA 11158 on Feb 14, 2011. A GPU-accelerated direct boundary integral equation (DBIE) method is implemented. This is about 1000 times faster than the original DBIE used on solar NLFFF modeling. Using the SDO/HMI vector magnetogram as the bottom boundary condition, the reconstructed magnetic field lines are compared with the projected EUV loop structures from different views three-dimensionally by SDO/AIA and STEREO A/B spacecraft simultaneously for the first time. They show very good agreement so that the topological configurations of the magnetic fields can be analyzed, thus its role in the flare process of the active region can be better understood. A quantitative comparison with some stereoscopically reconstructed coronal loops shows that the present averaged misalignment angles are at the same order as the state-of-the-art results obtained with reconstructed coronal loops as prescribed conditions and better than other NLFFF methods. It is found that the observed coronal loop structures can be grouped into bundles of closed and open loops with some central bright coronal loops around the polarity inversion line (PIL). The reconstructed highly-shearing magnetic field lines agree very well with the low-lying S-shaped filament channel along PIL. They are in a pivot position to all other surrounding coronal structures, and a group of electric current lines co-aligned with the central bright EUV loops overlying the filament channel is also obtained. This central lower-lying magnetic field loop system must have played a key role in powering the flare. It should be noted that while a strand-like coronal feature along PIL may be related to the filament, one cannot simply attribute all the coronal bright features along PIL to manifestation of the filament without any stereoscopically information. It shows that DBIE is rigorous and effective.

Solar Physics, accepted

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Cited by in corpus (8)

• The Magnetic Field of Active Region 11158 During the 2011 February 12-17 Flares : Differences between Photospheric Extrapolation and Coronal Forward-Fitting Methods
• Solar Flare Prediction Using Magnetic Field Diagnostics Above the Photosphere
• The nonpotentiality of coronae of solar active regions, the dynamics of the surface magnetic field, and the potential for large flares
• A Study of Magnetic Field Characteristics of Flaring Active Region Based on Nonlinear Force-free Field Extrapolation
• Relationship between Successive Flares in the Same Active Region and Space-Weather HMI Active Region Patch (SHARP) Parameters
• Photospheric Magnetic Free Energy Density of Solar Active Regions
• A Solar Eruption with Relatively Strong Geo-effectiveness Originating from Active Region Peripheral Diffusive Polarities
• Chirality and magnetic configuration associated with two-ribbon solar flares: AR 10930 versus AR 11158