Constraining 3D Magnetic Field Extrapolations Using The Twin Perspectives of STEREO

Abstract

The 3D magnetic topology of a solar active region (NOAA 10956) was reconstructed using a linear force-free field extrapolation constrained using the twin perspectives of \emph{STEREO}. A set of coronal field configurations was initially generated from extrapolations of the photospheric magnetic field observed by the Michelson Doppler Imager (MDI) on \emph{SOHO}. Using an EUV intensity-based cost function, the extrapolated field lines that were most consistent with 171Å passband images from the Extreme UltraViolet Imager (EUVI) on \emph{STEREO} were identified. This facilitated quantitative constraints to be placed on the twist ($\alpha$) of the extrapolated field lines, where $\nabla \times \mathbf{B}=\alpha \mathbf{B}$. Using the constrained values of $\alpha$, the evolution in time of twist, connectivity, and magnetic energy were then studied. A flux emergence event was found to result in significant changes in the magnetic topology and total magnetic energy of the region.

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Cited by in corpus (10)

• How to optimize nonlinear force-free coronal magnetic field extrapolations from SDO/HMI vector magnetograms?
• Magnetic Field Extrapolations in the Corona: Success and Future Improvements
• First 3D Reconstructions of Coronal Loops with the STEREO A+B Spacecraft: IV. Magnetic Modeling with Twisted Force-Free Fields
• Nonlinear Force-Free Magnetic Field Fitting to Coronal Loops with and without Stereoscopy
• A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. I. Theory
• Bootstrapping the Coronal Magnetic Field with STEREO: I. Unipolar Potential Field Modeling
• A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. III. The Free Energy
• Towards a Quantitative Comparison of Magnetic Field Extrapolations and Observed Coronal Loops
• Optimizing Global Coronal Magnetic Field Models Using Image-Based Constraints
• Image-Optimized Coronal Magnetic Field Models