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Possibilities in principle for satisfactory removal of the 180-azimuthal ambiguity in the transverse field of vector magnetograms and the extrapolation of magnetic fields independently of their position on the solar disk are shown. Revealed…

Solar and Stellar Astrophysics · Physics 2010-07-05 G. V. Rudenko , I. I. Myshyakov , S. A. Anfnogentov

Presently, many models of the coronal magnetic field rely on photospheric vector magnetograms but these data have been shown to be problematic as the sole boundary information for nonlinear force-free field (NLFFF) extrapolations. Magnetic…

Solar and Stellar Astrophysics · Physics 2021-06-29 A. Malanushenko , C. J. Schrijver , M. L. DeRosa , M. S. Wheatland , S. A. Gilchrist

We developed a code for the reconstruction of nonlinear force-free and non-force-free coronal magnetic fields. The 3D magnetic field is computed numerically with the help of an optimization principle. The force-free and non-force-free codes…

Astrophysics · Physics 2009-06-25 T. Wiegelmann

The 3D structure of an active region (AR) filament is studied using nonlinear force-free field (NLFFF) extrapolations based on simultaneous observations at a photospheric and a chromospheric height. To that end, we used the Si I 10827 \AA\…

Solar and Stellar Astrophysics · Physics 2015-06-03 L. Yelles Chaouche , C. Kuckein , V. Martínez Pillet , F. Moreno-Insertis

We present a new improved version of our force-free electrodynamics (FFE) numerical code in spherical coordinates that extrapolates the magnetic field in the inner solar corona from a photospheric vector magnetogram. The code satisfies the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Ioannis Contopoulos

Three-dimensional (3D) magnetic field in the solar atmosphere provides crucial information to understand the explosive phenomenon such as solar flares and coronal mass ejections. Since it is still hard that we determine the 3D magnetic…

Solar and Stellar Astrophysics · Physics 2026-01-07 Daiki Yamasaki , Takahiro Miyoshi , Satoshi Inoue

We derive an analytical approximation of nonlinear force-free magnetic field solutions (NLFFF) that can efficiently be used for fast forward-fitting to solar magnetic data, constrained either by observed line-of-sight magnetograms and…

Solar and Stellar Astrophysics · Physics 2014-03-27 Markus J. Aschwanden

Photospheric magnetic vector maps from two different instruments are used to model the nonlinear force-free coronal magnetic field above an active region. We use vector maps inferred from polarization measurements of the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2015-06-15 J. K. Thalmann , S. K. Tiwari , T. Wiegelmann

Quantum electrodynamics (QED) effects may be included in physical processes of magnetar and pulsar magnetospheres with strong magnetic fields. Involving the quantum corrections, the Maxwell electrodynamics is modified to non-linear…

High Energy Astrophysical Phenomena · Physics 2020-04-15 Huiquan Li , Xiaolin Yang , Jiancheng Wang

A magnetic field is force-free if there is no interaction between the magnetic field and plasma in surrounding atmosphere i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. Computation of various…

Solar and Stellar Astrophysics · Physics 2015-05-30 Sanjiv Kumar Tiwari

The Potential Field Source Surface (PFSS) model is the most used approach for extrapolating the global coronal magnetic field, offering efficiency and strong performance at large scales. However, PFSS assumes a potential coronal field, so…

Solar and Stellar Astrophysics · Physics 2026-03-23 C. Antonio , I. Chifu , R. Gafeira , J. J. G. Lima

Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated…

An interpolation method to evaluate magnetic fields given unstructured, scattered magnetic data is presented. The method is based on the reconstruction of the global magnetic field using a superposition of orthogonal functions. The…

Computational Physics · Physics 2023-03-15 Minglei Yang , Diego del-Castillo-Negrete , Guannan Zhang , Matthew Beidler

We use SDO/HMI and SOLIS/VSM photospheric magnetic field measurements to model the force-free coronal field above a solar active region, assuming magnetic forces to dominate. We take measurement uncertainties caused by, e.g., noise and the…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. K. Thalmann , A. Pietarila , X. Sun , T. Wiegelmann

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

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…

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

Magnetic field plays an important role in various solar eruptions like flares, coronal mass ejections, etc. The formation and evolution of characteristic magnetic field topology in solar eruptions are critical problems that will ultimately…

Solar and Stellar Astrophysics · Physics 2023-06-07 Wen He , Qiang Hu , Ju Jing , Haimin Wang , Chaowei Jiang , Sushree S. Nayak , Avijeet Prasad

The solar atmosphere being magnetic in nature, the understanding of the structure and evolution of the magnetic field in different regions of the solar atmosphere has been an important task over the past decades. This task has been made…

Solar and Stellar Astrophysics · Physics 2015-06-16 S. Regnier

Between 2008/3/24 and 2008/4/2, the three active regions NOAA active regions 10987, 10988 and 10989 were observed daily by the Synoptic Optical Long-term Investigations of the Sun (SOLIS) Vector Spectro-Magnetograph (VSM) while they…

Solar and Stellar Astrophysics · Physics 2015-05-20 Gordon Petrie , Aurelien Canou , Tahar Amari