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The potential field source surface (PFSS) method is a widely used magnetic field extrapolation technique in the space weather community. The only free parameter in the PFSS method is the source-surface height ($R_{\rm SS}$), beyond which…

Solar and Stellar Astrophysics · Physics 2025-10-16 Munehito Shoda , Kyogo Tokoro , Daikou Shiota , Shinsuke Imada

The performance of numerical micromagnetic models is limited by the demagnetizing field computation, which typically accounts for the majority of the computation time. For magnetization dynamics simulations explicit evaluation methods are…

Computational Physics · Physics 2022-06-15 Serban Lepadatu

A nonlinear force-free solution is constructed for the coronal magnetic field in NOAA solar active region AR 10953 based on a photospheric vector magnetogram derived from Hinode satellite observations on 30 April 2007, taking into account…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. S. Wheatland , K. D. Leka

Nonlinear force-free solutions for the magnetic field in the solar corona constructed using photospheric vector magnetic field boundary data suffer from a basic problem: the observed boundary data are inconsistent with the nonlinear…

Solar and Stellar Astrophysics · Physics 2009-07-22 M. S. Wheatland , S. Regnier

With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations. The object is…

Astrophysics · Physics 2009-11-13 S. Regnier , E. R. Priest

The magnetic field shapes the structure of the solar corona but we still know little about the interrelationships between the coronal magnetic field configurations and the resulting quasi-stationary structures observed in coronagraphic…

A more accurate analytical solution of the {\sl vertical-current approximation nonlinear force-free field (VCA3-NLFFF)} model is presented that includes besides the radial $(B_r)$ and the azimuthal $(B_\varphi)$ magnetic field components a…

Solar and Stellar Astrophysics · Physics 2020-01-08 Markus J. Aschwanden

[..] The change in the magnetic configuration due to the increase/decrease of electric current for different force-free models (potential, linear and nonlinear force-free fields) has never been studied in detail before. Here we focus…

Solar and Stellar Astrophysics · Physics 2015-05-28 S. Regnier

To understand the physics of solar flares, including the local reorganisation of the magnetic field and the acceleration of energetic particles, we have first to estimate the free magnetic energy available for such phenomena, which can be…

Astrophysics · Physics 2008-05-16 S. Regnier , E. R. Priest

Potential magnetic field solutions can be obtained based on the synoptic magnetograms of the Sun. Traditionally, a spherical harmonics decomposition of the magnetogram is used to construct the current and divergence free magnetic field…

Solar and Stellar Astrophysics · Physics 2011-05-02 Gabor Toth , Bart van der Holst , Zhenguang Huang

Investigating the solar magnetic field is crucial to understand the physical processes in the solar interior as well as their effects on the interplanetary environment. We introduce a novel method to predict the evolution of the solar…

This paper describes a new 2D model for the photospheric evolution of the magnetic carpet. It is the first in a series of papers working towards constructing a realistic 3D non-potential model for the interaction of small-scale solar…

Solar and Stellar Astrophysics · Physics 2011-08-05 Karen A. Meyer , Duncan H. Mackay , Adriaan A. van Ballegooijen , Clare E. Parnell

This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled in order to estimate the magnetic…

Astrophysics · Physics 2009-11-13 R. K. Ulrich , L. Bertello , J. E. Boyden , L. Webster

The internal dynamics of the Sun generate magnetic and plasma structures in the photosphere and overlying atmosphere across a wide range of spatial scales. Identifying the critical spatial scale is essential for interpreting physical…

Solar and Stellar Astrophysics · Physics 2026-04-14 Ananya Hore , Prantika Bhowmik

Full disk vector magnetic fields are used widely for developing better understanding of large-scale structure, morphology, and patterns of the solar magnetic field. The data are also important for modeling various solar phenomena. However,…

Solar and Stellar Astrophysics · Physics 2021-01-19 Alexei A. Pevtsov , Yang Liu , Ilpo Virtanen , Luca Bertello , Kalevi Mursula , K. D. Leka , Anna L. H. Hughes

A new method for reconstruction of coronal magnetic fields as force-free fields (FFFs) is presented. Our method employs poloidal and toroidal functions to describe divergence-free magnetic fields. This magnetic field representation…

Solar and Stellar Astrophysics · Physics 2022-10-04 Sibaek Yi , G. S. Choe , Kyung-Suk Cho , Sami K. Solanki , Jörg Büchner

We demonstrate the sensitivity of magnetic energy and helicity computations regarding the quality of the underlying coronal magnetic field model. We apply the method of Wiegelmann & Inhester (2010) to a series of SDO/HMI vector…

Solar and Stellar Astrophysics · Physics 2019-07-24 Julia K. Thalmann , Luis Linan , Etienne Pariat , Gherardo Valori

Context. A proper estimate of the chromospheric magnetic fields is believed to improve modelling of both active region and coronal mass ejection evolution. Aims. We investigate the similarity between the chromospheric magnetic field…

Recent advances in spectropolarimetry have allowed the reconstruction of stellar coronal magnetic fields. This uses Zeeman-Doppler magnetograms of the surface magnetic field as a lower boundary condition. The ZDI maps, however, suffer from…

Solar and Stellar Astrophysics · Physics 2015-05-18 Colin Johnstone , Moira Jardine , Duncan Mackay

Coupled flux transport and magneto-frictional simulations are extended to simulate the continuous magnetic field evolution in the global solar corona for over 15 years, from the start of Solar Cycle 23 in 1996. By simplifying the dynamics,…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. R. Yeates