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Computational Fluid Dynamics (CFD)-based global solar coronal simulations are slowly making their way into the space weather modeling toolchains to replace the semi-empirical methods such as the Wang-Sheeley-Arge (WSA) model. However, since…

Solar and Stellar Astrophysics · Physics 2023-03-21 Michaela Brchnelova , Błażej Kuźma , Fan Zhang , Barbara Perri , Andrea Lani , Stefaan Poedts

We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Philip G. Judge , Shadia Habbal , Enrico Landi

The magneto-frictional method is used in solar physics to compute both static and quasi-static models of the Sun's coronal magnetic field. Here, we examine how accurately magneto-friction (without fluid pressure) is able to predict the…

Solar and Stellar Astrophysics · Physics 2022-01-20 A. R. Yeates

It was recently proposed that the intensity ratios of several extreme ultraviolet spectral lines from the Fe X ion can be used to measure the solar coronal magnetic field based on the magnetic-field-inducedtransition (MIT) theory. To verify…

Solar and Stellar Astrophysics · Physics 2021-10-27 Yajie Chen , Wenxian Li , Hui Tian , Feng Chen , Xianyong Bai , Yang Yang , Zihao Yang , Xianyu Liu , Yuanyong Deng

We performed a magnetohydrodynamic (MHD) simulation using a nonlinear force-free field (NLFFF) in solar active region 11158 to clarify the dynamics of an X2.2-class solar flare. We found that the NLFFF never shows the drastic dynamics seen…

Solar and Stellar Astrophysics · Physics 2015-06-19 S. Inoue , K. Hayashi , T. Magara , G. S. Choe , Y. D. Park

Recent advances have made it possible to obtain two-dimensional line-of-sight magnetic field maps of the solar corona from spectropolarimetric observations of the Fe XIII 1075 nm forbidden coronal emission line. Together with the linear…

Astrophysics · Physics 2009-11-13 Yu Liu , Haosheng Lin

In this work, we extend the source-free (SF) exchange correlation (XC) functional developed by Sangeeta Sharma and co-workers to plane-wave density functional theory (DFT) based on the projector augmented wave (PAW) method. This constraint…

Materials Science · Physics 2024-05-28 Guy C. Moore , Matthew K. Horton , Aaron D. Kaplan , Sinéad M. Griffin , Kristin A. Persson

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

Force-freeness of a solar magnetic field is a key to reconstructing invisible coronal magnetic structure of an emerging flux region on the Sun where active phenomena such as flares and coronal mass ejections frequently occur. We have…

Solar and Stellar Astrophysics · Physics 2015-06-23 Jihye Kang , Tetsuya Magara

We derived the coronal magnetic field, plasma density, and temperature from the observation of polarization and intensity of radio thermal free-free emission using the Nobeyama Radioheliograph (NoRH) and extreme ultraviolet (EUV)…

Many magnetic structures in the solar atmosphere evolve rather slowly so that they can be assumed as (quasi-)static or (quasi-)stationary and represented via magneto-hydrostatic (MHS) or stationary magneto-hydrodynamic (MHD) equilibria,…

Solar and Stellar Astrophysics · Physics 2017-03-15 Dieter H. Nickeler , Thomas Wiegelmann , Marian Karlicky , Michaela Kraus

Previous studies have found that coronal loops have a nearly uniform thickness, which seems to disagree with the characteristic expansion of active region magnetic fields. This is one of the most intriguing enigmas in solar physics. We here…

Astrophysics · Physics 2009-11-13 M. C. Lopez Fuentes , J. A. Klimchuk , P. Demoulin

The development of systematic effective field theories (EFTs) for nuclear forces and advances in solving the nuclear many-body problem have greatly improved our understanding of dense nuclear matter and the structure of finite nuclei. For…

Nuclear Theory · Physics 2025-09-30 Brendan T. Reed , Matthias Heinz , Pierre Arthuis , Achim Schwenk , Ingo Tews

Aims. We show how the build-up of magnetic gradients in the Sun's corona may be inferred directly from photospheric velocity data. This enables computation of magnetic connectivity measures such as the squashing factor without recourse to…

Solar and Stellar Astrophysics · Physics 2015-05-30 A. R. Yeates , G. Hornig , B. T. Welsch

Force-free electrodynamics describes the electromagnetic field of the magnetically dominated plasma found near pulsars and active black holes, but gives no information about the underlying particles that ultimately produce the observable…

High Energy Astrophysical Phenomena · Physics 2025-11-05 Morifumi Mizuno , Samuel E. Gralla , Alexander Philippov

Magnetar magnetospheres gradually become twisted due to shearing by footpoint motion. The axisymmetric solutions for the force-free field with a power-law current model are calculated by taking into account general relativistic effects.…

High Energy Astrophysical Phenomena · Physics 2017-04-19 Yasufumi Kojima

This paper describes the electrodynamics of a null and force-free field in completely geometric terms. As was previously established in \cite{Menon_FF20}, solutions to force-free electrodynamics are governed by the existence of certain…

General Relativity and Quantum Cosmology · Physics 2021-02-03 Govind Menon

Solar flares are driven by release of free magnetic energy and often associated with restructurization of the magnetic field topology. Yet, observations of evolving magnetic field in the flaring volume are limited to very few cases…

Solar and Stellar Astrophysics · Physics 2026-02-18 Gregory D. Fleishman , Tatyana Kaltman , Sijie Yu

A method is derived to obtain an expansion formula for the magnetic field $\boldsymbol{B}(\boldsymbol{r})$ generated by a closed planar wire carrying a steady electric current. The parametric equation of the loop is…

General Physics · Physics 2021-08-18 Robert Salazar , Gabriel Téllez , Camilo Bayona-Roa

The dynamics of highly magnetized plasmas in extreme astrophysical environments are effectively modeled by Force-Free Electrodynamics (FFE), a framework essential for studying objects like neutron stars and accreting black holes. The…

General Relativity and Quantum Cosmology · Physics 2025-11-11 Rakshak Adhikari