Force-free Field Reconstructions Enhanced by Chromospheric Magnetic Field Data

Abstract

Abstract A 3D picture of the coronal magnetic field remains an outstanding problem in solar physics, particularly in active regions. Nonlinear force-free field reconstructions that employ routinely available full-disk photospheric vector magnetograms represent state-of-the-art coronal magnetic field modeling. Such reconstructions, however, suffer from an inconsistency between a force-free coronal magnetic field and a non-force-free photospheric boundary condition, from which the coronal reconstruction is performed. In this study we focus on integrating the additional chromospheric and/or coronal magnetic field data with the vector photospheric magnetograms with the goal of improving the reliability of the magnetic field reconstructions. We develop a corresponding modification of the available optimization codes described in Fleishman et al. and test their performance using a full-fledged magnetohydrodynamics model obtained from the Bifrost code by performing a “voxel-by-voxel” comparison between the reconstructed and the model magnetic fields. We demonstrate that adding even an incomplete set of chromospheric magnetic field data can measurably improve the reconstruction of the coronal magnetic field and greatly improve reconstructions of the magnetic connectivity and of the coronal electric current.