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The primary focus of this paper is on the particle acceleration mechanism in solar coronal three-dimensional reconnection null-point regions. Starting from a potential field extrapolation of a Solar and Heliospheric Observatory (SOHO)…

Solar and Stellar Astrophysics · Physics 2013-07-09 G. Baumann , T. Haugbølle , Å. Nordlund

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

Accreting supermassive black holes can now be observed at the event-horizon scale at mm wavelengths. Current predictions for the image rely on hypotheses (fluid modeling, thermal electrons) which might not always hold in the vicinity of the…

High Energy Astrophysical Phenomena · Physics 2022-11-23 Benjamin Crinquand , Benoît Cerutti , Guillaume Dubus , Kyle Parfrey , Alexander A. Philippov

This paper focuses on the 2D compressible magnetohydrodynamic (MHD) equations without magnetic diffusion in a periodic domain. We present a systematic approach to establishing the global existence of smooth solutions when the initial data…

Analysis of PDEs · Mathematics 2022-06-22 Jiahong Wu , Yi Zhu

An instability criterion in the MHD with the open boundary of magnetic field is proposed in this paper. We use a series of linear force-free extrapolation field, in which the normal part of magnetic field is fixed, to obtain the linear…

Solar and Stellar Astrophysics · Physics 2024-12-25 Shangbin Yang , Joerg Buechner , Jean Carlo Santos , Jan Skala , Hongqi Zhang

We present a new MHD wave decomposition method that overcomes the limitations of existing wave identification methods. Our method allows to investigate the energy fluxes in different MHD modes at different locations of the solar atmosphere…

Solar and Stellar Astrophysics · Physics 2022-04-20 N. Yadav , Rony Keppens , B. Popescu Braileanu

COCONUT is a global coronal magnetohydrodynamic model recently developed. In order to achieve robustness and fast convergence to steady-state, several assumptions have been made during its development, such as prescribing filtered…

Solar and Stellar Astrophysics · Physics 2023-06-16 Michaela Brchnelova , Błażej Kuźma , Fan Zhang , Andrea Lani , Stefaan Poedts

We use three dimensional magnetohydrodynamic simulations to study the structure of the boundary layer between an accretion disc and a non-rotating, unmagnetized star. Under the assumption that cooling is efficient, we obtain a narrow but…

Astrophysics · Physics 2009-11-07 Philip J. Armitage

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…

Using solar wind observation near PSP perihelions as constraints, we have investigated the parameters in various PFSS model methods. It's found that the interplanetary magnetic field extrapolation with source surface height $R_\mathrm{SS} =…

Solar and Stellar Astrophysics · Physics 2023-05-23 Yuechun Song

Magnetic helicity has the remarkable property of being a conserved quantity of ideal magnetohydrodynamics (MHD). Therefore, it could be used as an effective tracer of the magnetic field evolution of magnetized plasmas. Theoretical…

Solar and Stellar Astrophysics · Physics 2015-08-19 E. Pariat , G. Valori , P. Démoulin , K. Dalmasse

A putative temporally varying circulation-free magnetic-field configuration is inferred in an equatorial segment of the solar convection zone from the helioseismologically inferred angular-velocity variation, assuming that the predominant…

Solar and Stellar Astrophysics · Physics 2015-06-11 H. M. Antia , S. M. Chitre , D. O. Gough

A necessary and sufficient set of conditions for a quasisymmetric magnetic field in the form of constraint equations is derived from first principles. Without any assumption regarding the magnetohydrodynamic (MHD) equilibrium of the plasma,…

Plasma Physics · Physics 2020-06-24 Eduardo Rodriguez , Per Helander , Amitava Bhattacharjee

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

Filaments are special plasma phenomena embedded in the solar atmosphere, characterized by unique thermodynamic properties and magnetic structures. Magnetohydrodynamic (MHD) simulations are useful to investigate the eruption mechanisms of…

Solar and Stellar Astrophysics · Physics 2025-04-22 Yihua Li , Yang Guo , Jinhan Guo , M. D. Ding , Chun Xia , Rony Keppens

Extrapolation codes for modelling the magnetic field in the corona in cartesian geometry do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, \textit{e.g.}, a single active region.…

Solar and Stellar Astrophysics · Physics 2011-04-13 T. Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

Finding low-mass planets around solar-type stars requires to understand the physical variability of the host star, which greatly exceeds the planet-induced radial-velocity modulation. Different solar photospheric absorption lines have…

Solar and Stellar Astrophysics · Physics 2026-04-16 Dainis Dravins , Hans-Günter Ludwig , Matthias Steffen , Carlos Allende Prieto , Lars Koesterke

Magnetic flux is continuously being removed and replenished on the solar surface. To understand the removal process we carried out 3D radiative MHD simulations of the evolution of patches of photospheric magnetic field with equal amounts of…

Solar and Stellar Astrophysics · Physics 2015-05-30 Robert Cameron , Alexander Voegler , Manfred Schuessler

Structures seen in idealized numerical experiments on compressible magnetoconvection in an imposed strong vertical magnetic field show important differences from those detected in observations or realistic numerical simulations of sunspot…

Solar and Stellar Astrophysics · Physics 2016-03-08 C. Tian , K. Petrovay

We present, for the first time, the structure of the axisymmetric force-free magnetosphere of an aligned rotating magnetic dipole, in the case in which there exists a sufficiently large charge density (whose origin we do not question) to…

Astrophysics · Physics 2011-07-18 Ioannis Contopoulos , Demosthenes Kazanas , Christian Fendt