Coronal Magnetic Field Structure and Evolution for Flaring AR 11117 and its Surroundings

TL;DR

This paper models the 3D coronal magnetic fields of active region AR 11117 using vector magnetograms, analyzing its evolution and energy changes before and after a solar flare to understand magnetic connectivity and energy release.

Contribution

It introduces a method to model the nonlinear force-free coronal magnetic fields in spherical geometry and compares magnetic configurations pre- and post-flare in AR 11117.

Findings

Estimated free magnetic energy change of 1.74x10^{32} erg.

Disruption of electric currents between AR 11117 and surroundings after the flare.

Magnetic topology and energy density variations observed.

Abstract

In this study, photospheric vector magnetograms obtained with the Synoptic Optical Long-term Investigations of the Sun survey (SOLIS), are used as boundary conditions to model the three-dimensional nonlinear force-free (NLFF) coronal magnetic fields as a sequence of nonlinear force-free equilibria in spherical geometry. We study the coronal magnetic field structure inside active regions and its temporal evolution. We compare the magnetic field configuration obtained from NLFF extrapolation before and after flaring event in active region (AR) 11117 and its surroundings observed on 27 October 2010. We compare the magnetic field topologies and the magnetic energy densities and study the connectivities between AR 11117 and its surroundings. During the investigated time period, we estimate the change in free magnetic energy from before to after the flare to be 1.74x10^{32}erg which represents about 13.5% of nonlinear force-free magnetic energy before the flare. In this study, we find that electric currents from AR 11117 to its surroundings were disrupted after the flare.