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Related papers: Magnetohydrostatic modelling of stellar coronae

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We study the thermodynamics of the Hamiltonian Mean Field (HMF) model with an external potential playing the role of a "magnetic field". If we consider only fully stable states, this system does not present any phase transition. However, if…

Statistical Mechanics · Physics 2015-05-20 Pierre-Henri Chavanis

We present two-dimensional, cylindrically symmetric simulations of hydrodynamic and magnetohydrodynamic (MHD) wide-angle winds interacting with a collapsing environment. These simulations have direct relevance to young stellar objects…

Astrophysics · Physics 2009-11-07 T. A. Gardiner , A. Frank , L. Hartmann

We re-analyse spectropolarimetric data of AB Dor taken in 1996 December using a surface imaging code that can model the magnetic field of the star as a non-potential current-carrying magnetic field. We find that a non-potential field needs…

Astrophysics · Physics 2009-11-07 G. A. J. Hussain , A. A. van Ballegooijen , M. Jardine , A. Col lier Cameron

We construct two classes of the magnetohydrostatic equilibria of the axisymmetric flux tubes with twisted magnetic fields in the stratified solar atmosphere that span from the photosphere to the transition region. We built the models by…

Solar and Stellar Astrophysics · Physics 2021-03-31 S. Sen , A. Mangalam

We describe, test, and apply a technique to incorporate full-sun, surface flux evolution into an MHD model of the global solar corona. Requiring only maps of the evolving surface flux, our method is similar to that of Lionello et al.…

Solar and Stellar Astrophysics · Physics 2023-10-12 Roberto Lionello , Cooper Downs , Emily I. Mason , Jon A. Linker , Ronald M. Caplan , Pete Riley , Viacheslav S. Titov , Marc L. DeRosa

We present a novel magnetohydrostatic numerical model that solves directly for the force-balanced magnetic field in the solar corona. This model is constructed with Radial Basis Function Finite Differences (RBF-FD), specifically 3D…

Solar and Stellar Astrophysics · Physics 2022-05-11 Nathaniel H. Mathews , Natasha Flyer , Sarah E. Gibson

In this review, our present day understanding of the Sun's global photospheric and coronal magnetic fields is discussed from both observational and theoretical viewpoints. Firstly, the large-scale properties of photospheric magnetic fields…

Solar and Stellar Astrophysics · Physics 2015-06-12 D. H. Mackay , A. R. Yeates

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

Our understanding of the structure and dynamics of stellar coronae has changed dramatically with the availability of surface maps of both star spots and also magnetic field vectors. Magnetic field extrapolations from these surface maps…

Solar and Stellar Astrophysics · Physics 2015-05-19 Moira Jardine , Jean-Francois Donati , Doris Arzoumanian , Aline de Vidotto

Macroscopic wave and oscillatory phenomena ubiquitously detected in the plasma of the corona of the Sun are interpreted in terms of magnetohydrodynamic theory. Fast and slow magnetoacoustic waves are clearly distinguished in observations.…

Solar and Stellar Astrophysics · Physics 2024-04-02 Valery M. Nakariakov , Sihui Zhong , Dmitrii Y. Kolotkov , Rebecca L. Meadowcroft , Yu Zhong , Ding Yuan

The magnetic field governs the corona; hence it is a crucial parameter to measure. Unfortunately, existing techniques for estimating its strength are limited by strong assumptions and limitations. These techniques include photospheric or…

Solar and Stellar Astrophysics · Physics 2022-10-26 Juan Martinez-Sykora , Viggo H. Hansteen , Bart De Pontieu , Enrico Landi

We present a self-similar, steady-state model describing both a magnetized accretion disc and a magnetohydrodynamic jet. We focus on the role of a hot corona in such a structure. This corona enables the disc to launch various types of jets.…

Astrophysics · Physics 2007-05-23 Fabien Casse , Jonathan Ferreira

Maps of the radial magnetic field at a heliocentric distance of ten solar radii are used as boundary conditions in the MHD code CRONOS to simulate a 3D inner-heliospheric solar wind emanating from the rotating Sun out to 1 AU. The input…

Space Physics · Physics 2013-03-19 T. Wiengarten , J. Kleimann , H. Fichtner , R. Cameron , J. Jiang , R. Kissmann , K. Scherer

An hourglass-shaped magnetic field pattern arises naturally from the gravitational collapse of a star-forming gas cloud. Most studies have focused on the prestellar collapse phase, when the structure has a smooth and monotonic radial…

Solar and Stellar Astrophysics · Physics 2024-06-10 Shantanu Basu , Xiyuan Li , Gianfranco Bino

Temperature contrasts and magnetic field strengths of sunspot umbrae broadly follow the thermal-magnetic relationship obtained from magnetohydrostatic equilibrium. Using a compilation of recent observations, especially in molecular bands,…

Solar and Stellar Astrophysics · Physics 2015-05-20 S. P. Rajaguru , S. S. Hasan

We present a method to include stereoscopic information about the three dimensional structure of flux tubes into the reconstruction of the coronal magnetic field. Due to the low plasma beta in the corona we can assume a force free magnetic…

Astrophysics · Physics 2015-05-13 T. Wiegelmann , T. Neukirch

The origin and evolution of the magnetic helicity in the solar corona are not well understood. For instance, the magnetic helicity of an active region is often about $10^{42}$ Mx$^2$ ($10^{26}$ Wb$^{2}$), but the observed processes whereby…

Solar and Stellar Astrophysics · Physics 2009-11-13 S. Regnier

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

Modeling the solar atmosphere is challenging due to its layered structure and multi-scale dynamics. We aim to validate the new radiative MHD code MAGEC, which combines the MANCHA and MAGNUS codes into a finite-volume, shock-capturing…

Solar and Stellar Astrophysics · Physics 2025-11-10 Anamaría Navarro , E. Khomenko , N. Vitas , T. Felipe

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
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