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Deriving the strength and direction of the three-dimensional (3D) magnetic field in the solar atmosphere is fundamental for understanding its dynamics. Volume information on the magnetic field mostly relies on coupling 3D reconstruction…

Solar and Stellar Astrophysics · Physics 2019-06-05 K. Dalmasse , A. Savcheva , S. E. Gibson , Y. Fan , D. W. Nychka , N. Flyer , N. Mathews , E. E. DeLuca

Solar image analysis relies on the detection of coronal holes for predicting disruptions to earth's magnetic field. The coronal holes act as sources of solar wind that can reach the earth. Thus, coronal holes are used in physical models for…

Solar and Stellar Astrophysics · Physics 2022-07-21 Venkatesh Jatla

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…

[..] 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

The coronal magnetic field directly or indirectly affects a majority of the phenomena studied in space physics. It provides energy for coronal heating, controls the release of coronal mass ejections (CMEs), and drives heliospheric and…

Solar and Stellar Astrophysics · Physics 2016-04-13 Shaela I. Jones , Joseph M. Davila , Vadim M. Uritsky

Recently, it has been proposed that the magnetic-field-induced transition (MIT) in Fe X can be used to measure coronal magnetic field strengths. Several techniques, the direct line ratio technique and the weak and strong magnetic field…

Solar and Stellar Astrophysics · Physics 2023-03-08 Yajie Chen , Xianyong Bai , Hui Tian , Wenxian Li , Feng Chen , Zihao Yang , Yang Yang

The minimum-energy configuration for the magnetic field above the solar photosphere is curl-free (hence, by Ampere's law, also current-free), so can be represented as the gradient of a scalar potential. Since magnetic fields are divergence…

Solar and Stellar Astrophysics · Physics 2016-06-20 Brian T. Welsch , George H. Fisher

Context: In this paper we present a validation scheme to investigate the quality of coronal magnetic field models, which is based upon comparisons with observational data from multiple sources. Aims: Many of these coronal models may use a…

Solar and Stellar Astrophysics · Physics 2022-02-09 A. Wagner , E. Asvestari , M. Temmer , S. G. Heinemann , J. Pomoell

CONTEXT: As the coronal magnetic field can usually not be measured directly, it has to be extrapolated from photospheric measurements into the corona. AIMS: We test the quality of a non-linear force-free coronal magnetic field extrapolation…

Current sheets are essential for energy dissipation in the solar corona, in particular by enabling magnetic reconnection. Unfortunately, sufficiently thin current sheets cannot be resolved observationally and the theory of their formation…

Astrophysics · Physics 2025-07-21 Joerg Buechner

We study the magnetic field and current structure associated with a coronal loop. Through this we investigate to what extent the assumptions of a force-free magnetic field break down and where they might be justified. We analyse a 3D MHD…

Solar and Stellar Astrophysics · Physics 2017-12-05 Jörn Warnecke , Feng Chen , Sven Bingert , Hardi Peter

A nonlinear force-free field (NLFFF) extrapolation is widely used to reconstruct the three-dimensional magnetic field in the solar corona from the observed photospheric magnetic field. However, the pressure gradient and gravitational forces…

Solar and Stellar Astrophysics · Physics 2020-03-04 Takahiro Miyoshi , Kanya Kusano , Satoshi Inoue

Context. On the sun, the magnetic field vector is measured routinely only in the photosphere. By using these photospheric measurements as boundary condition, we developed the magnetohydrostatic (MHS) extrapolation to model the solar…

Solar and Stellar Astrophysics · Physics 2019-11-20 Xiaoshuai Zhu , Thomas Wiegelmann

Coronal and chromospheric magnetic fields are derived from polarization and spectral observations of the thermal free-free emission using the Nobeyama Radioheliograph (NoRH). In magnetized plasma, the ordinary and extraordinary modes of…

Solar and Stellar Astrophysics · Physics 2015-06-16 Kazumasa Iwai , Kiyoto Shibasaki

A 3-D coronal magnetic field is reconstructed for NOAA 11158 on Feb 14, 2011. A GPU-accelerated direct boundary integral equation (DBIE) method is implemented. This is about 1000 times faster than the original DBIE used on solar NLFFF…

Solar and Stellar Astrophysics · Physics 2015-06-16 Rui Wang , Yihua Yan , Baolin Tan

Previous work utilising NASA's High-resolution Coronal Imager (Hi-C 2.1) 17.2 nm observations revealed that, even at the increased spatial scales available in the data-set, there may be evidence for coronal structures that are still not…

Solar and Stellar Astrophysics · Physics 2020-10-21 Thomas Williams , Robert W. Walsh , Hardi Peter , Amy R. Winebarger

Measurements of the magnetic field in the stellar coronae are extremely difficult. Recently, it was proposed that the magnetic-field-induced transition (MIT) of the Fe X 257 {\AA} line can be used to measure the coronal magnetic field of…

Solar and Stellar Astrophysics · Physics 2021-09-08 Yajie Chen , Xianyu Liu , Hui Tian , Xianyong Bai , Meng Jin , Wenxian Li , Yang Yang , Zihao Yang , Yuanyong Deng

All three components of the current density are required to compute the heating rate due to free magnetic energy dissipation. Here we present a first test of a new model developed to determine if the times of increases in the resistive…

Solar and Stellar Astrophysics · Physics 2020-04-29 Michael L. Goodman , Chiman Kwan , Bulent Ayhan , Eric L. Shang

The potential field (PF) solution of the solar corona is a vital modeling tool for a wide range of applications, including minimum energy estimates, coronal magnetic field modeling, and empirical solar wind solutions. Given its popularity,…

Solar and Stellar Astrophysics · Physics 2021-07-14 Ronald M. Caplan , Cooper Downs , Jon A. Linker , Zoran Mikic

The variation of the vector magnetic field along structures in the solar corona remains unmeasured. Using a unique combination of spectropolarimetry and stereoscopy, we infer and compare the vector magnetic field structure and…

Solar and Stellar Astrophysics · Physics 2016-12-14 Thomas A. Schad , Matthew J. Penn , Haosheng Lin , Philip G. Judge
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