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Related papers: Nonlinear force-free field extrapolation in spheri…

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Magnetic field is the key physical quantity in solar physics as it controls all kinds of solar activity, ranging from nanoflares to big flares and coronal mass ejections (CMEs). However, so far only the magnetic field on the solar surface…

Solar and Stellar Astrophysics · Physics 2025-11-21 P. F. Chen

Estimating the magnetic field strength in the solar corona is crucial for understanding different physical processes happening over diverse spatio-temporal scales. However, the high temperatures and low density of the solar corona make this…

Solar and Stellar Astrophysics · Physics 2024-03-07 Upasna Baweja , Vaibhav Pant , Iñigo Arregui

We present a method for performing data-driven simulations of solar active region formation and evolution. The approach is based on magnetofriction, which evolves the induction equation assuming the plasma velocity is proportional to the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Mark C. M. Cheung , Marc L. DeRosa

Based on a second-order approximation of nonlinear force-free magnetic field solutions in terms of uniformly twisted field lines derived in Paper I, we develop here a numeric code that is capable to forward-fit such analytical solutions to…

Solar and Stellar Astrophysics · Physics 2015-06-05 Markus J. Aschwanden , Anna Malanushenko

We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general…

Astrophysics · Physics 2009-11-13 M. K. Georgoulis , Barry J. LaBonte

The characteristic electron densities, temperatures, and thermal distributions of 1MK active region loops are now fairly well established, but their coronal magnetic field strengths remain undetermined. Here we present measurements from a…

Solar and Stellar Astrophysics · Physics 2021-07-14 David H. Brooks , Harry P. Warren , Enrico Landi

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…

Solar and Stellar Astrophysics · Physics 2015-05-18 Paul A. Conlon , Peter T. Gallagher

Recent work suggested that the traditional picture of the corona above the quiet Sun being rooted in the magnetic concentrations of the chromospheric network alone is strongly questionable. Building on that previous study we explore the…

Astrophysics · Physics 2009-11-11 Stefan Jendersie , Hardi Peter

This paper is concerned with the Laplace boundary-value problem with the directional derivative, corresponding to the specific nature of measurements of the longitudinal component of the photospheric magnetic field. Boundary conditions are…

Astrophysics · Physics 2015-06-24 G. V. Rudenko

We re-analyse spectropolarimetric data of AB Dor taken in 1996 December using a surface imaging code that can model the magnetic field of the star as a non-potential current-carrying magnetic field. We find that a non-potential field needs…

Astrophysics · Physics 2009-11-07 G. A. J. Hussain , A. A. van Ballegooijen , M. Jardine , A. Col lier Cameron

We expand upon our paper (Rice and Yeates, 2021) which introduced `Outflow Fields': alternatives to the widely-used potential field source surface (PFSS) extrapolations of the Sun's coronal magnetic field which take into account the effect…

Solar and Stellar Astrophysics · Physics 2026-03-24 Oliver Rice , Anthony Yeates

The magnetic field plays an essential role in the initiation and evolution of different solar phenomena in the corona. The structure and evolution of the 3D coronal magnetic field are still not very well known. A way to get the 3D structure…

Solar and Stellar Astrophysics · Physics 2021-03-31 Iulia Chifu , Ricardo Gafeira

We examine the nonlinear magnetofrictional extrapolation scheme using the solar active region model by Titov and D\'emoulin as test field. This model consists of an arched, line-tied current channel held in force-free equilibrium by the…

Solar and Stellar Astrophysics · Physics 2015-05-18 G. Valori , B. Kliem , T. Török , V. S. Titov

Direct solar coronal magnetic field measurements have become possible since recent development of high-sensitivity infrared detection technology. The SOLARC instrument installed on Mt. Haleakala is such a polarimetric coronagraph that was…

Astrophysics · Physics 2008-09-05 Y. Liu , H. Lin

We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. J. D. Petrie

The solar active region (AR) 12192 was one of the most flare productive region of solar cycle 24, which produced many X-class flares; the most energetic being an X3.1 flare on October 24, 2014 at 21:10 UT. Customarily, such events are…

Solar and Stellar Astrophysics · Physics 2019-01-30 A. Prasad , R. Bhattacharyya , Q. Hu , S. S. Nayak , Sanjay Kumar

Potential Field Source Surface (PFSS) models are widely used to study the solar corona and form the basis for solar wind forecasting, yet often fail to reproduce observed properties of coronal holes. We analyze 702 observed coronal holes…

Solar and Stellar Astrophysics · Physics 2026-01-19 Stephan G. Heinemann , Jens Pomoell , Manuela Temmer

We developed a new nonlinear force-free magnetic field (NLFFF) forward-fitting algorithm based on an analytical approximation of force-free and divergence-free NLFFF solutions, which requires as input a line-of-sight magnetogram and traced…

Solar and Stellar Astrophysics · Physics 2013-05-24 Markus J. Aschwanden

In this paper, the statistical studies on the force-freeness of photosphere magnetic fields are given. The studies are based on the vector magnetic fields observed by Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) on board Hinode.…

Solar and Stellar Astrophysics · Physics 2019-02-04 S. Liu , J. Hao

The differential rotation of the solar corona for the period 1976-2004 was studied as a function of the distance from the center of the Sun. For this study, we developed a method using the coronal magnetic field as a tracer. The field in a…

Solar and Stellar Astrophysics · Physics 2018-09-19 O. G. Badalyan , V. N. Obridko