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Coronal holes and active regions are typical magnetic structures found in the solar atmosphere. We propose several magnetohydrostatic equilibrium solutions that are representative of these structures in two dimensions. Our models include…

Solar and Stellar Astrophysics · Physics 2022-12-15 J. Terradas , R. Soler , R. Oliver , P. Antolin , I. Arregui , M. Luna , I. Piantschitsch , E. Soubrié , J. L. , Ballester

Understanding structures and evolutions of the magnetic fields and plasma in multiple layers on the Sun is very important. A force-free magnetic field which is an accurate approximation of the solar corona due to the low plasma $\beta$ has…

Solar and Stellar Astrophysics · Physics 2022-03-30 Xiaoshuai Zhu , Thomas Neukirch , Thomas Wiegelmann

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

In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background stratified atmosphere and is connected to the…

Solar and Stellar Astrophysics · Physics 2015-06-23 J. Terradas , R. Soler , M. Luna , R. Oliver , J. L. Ballester

Our aim is to model the 3D magnetic field structure of the upper solar atmosphere, including regions of non-negligible plasma beta. We use high-resolution photospheric magnetic field measurements from SUNRISE/IMaX as boundary condition for…

Solar and Stellar Astrophysics · Physics 2015-12-09 T. Wiegelmann , T. Neukirch , D. H. Nickeler , S. K. Solanki , V. Martinez Pillet , J. M. Borrero

Context. High resolution magnetic field measurements are routinely done only in the solar photosphere. Higher layers like the chromosphere and corona can be modeled by extrapolating the photospheric magnetic field upward. In the solar…

Solar and Stellar Astrophysics · Physics 2020-08-26 Xiaoshuai Zhu , Thomas Wiegelmann , Sami Solanki

A solar active region (AR) is a three-dimensional magnetic structure formed in the convection zone, whose property is fundamentally important for determining the coronal structure and solar activity when emerged. However, our knowledge on…

Solar and Stellar Astrophysics · Physics 2013-01-22 Georgios Chintzoglou , Jie Zhang

Comprehending the manner in which magnetic fields affect propagating waves is a first step toward constructing accurate helioseismic models of active region sub-surface structure and dynamics. Here, we present a numerical method to compute…

Astrophysics · Physics 2009-11-13 Shravan M. Hanasoge

We present three-dimensional solutions of the magnetohydrostatic equations in the co-rotating frame of reference outside a magnetized rigidly rotating cylinder. We make no symmetry assumption for the magnetic field, but to be able to make…

Earth and Planetary Astrophysics · Physics 2009-11-30 Thomas Neukirch

Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with…

Solar and Stellar Astrophysics · Physics 2023-07-12 Fu Yu , Jie Zhao , Yang Su , Xiaoshuai Zhu , Yang Guo , Jinhua Shen , Hui Li

One-dimensional, semi-empirical models of the solar atmosphere are widely employed in numerous contexts within solar physics, ranging from the determination of element abundances and atomic parameters to studies of the solar irradiance and…

Solar and Stellar Astrophysics · Physics 2024-04-11 J. M. Borrero , I. Milic , A. Pastor Yabar , A. J. Kaithakkal , J. de la Cruz Rodriguez

Context. For the last thirty years, most of the studies on the relaxation of stressed magnetic fields in the solar environment have onlyconsidered the Lorentz force, neglecting plasma contributions, and therefore, limiting every equilibrium…

Solar and Stellar Astrophysics · Physics 2011-10-25 Jorge Fuentes-Fernández , Clare E. Parnell , Alan W. Hood

Magnetic fields and flows in coronal structures, for example, in gradual phases in flares, can be described by 2D and 3D magnetohydrostatic (MHS) and steady magnetohydrodynamic (MHD) equilibria. Within a physically simplified, but exact…

Solar and Stellar Astrophysics · Physics 2014-09-17 D. H. Nickeler , M. Karlicky , T. Wiegelmann , M. Kraus

Solar active regions are driven dissipative dynamical systems. The turbulent convection zone forces new magnetic flux tubes to rise above the photosphere and shuffles the magnetic fields which are already above the photosphere. The driven…

Astrophysics · Physics 2009-09-29 Loukas Vlahos

Statistical properties of the Sun's photospheric turbulent magnetic field, especially those of the Active Regions (ARs), have been studied using the line-of-sight data from magnetograms taken by SOHO and several other instruments (see e.g.…

Solar and Stellar Astrophysics · Physics 2013-07-17 Shiva Kumar. Malapaka , Wolf-Christian Mueller

The formation and evolution of active regions is an inherently complex phenomenon. Magnetic fields generated at the base of the convection zone follow a chaotic evolution before reaching the solar surface. In this article, we use a 2-D…

Astrophysics · Physics 2009-11-07 L. Vlahos , T. Fragos , H. Isliker , M. Georgoulis

We investigate the possible development of magnetohydrodynamical instabilities in the EULAG-MHD "millenium simulation" of Passos & Charbonneau (2014). This simulation sustains a large-scale magnetic cycle characterized by solar-like…

Solar and Stellar Astrophysics · Physics 2015-11-11 N. Lawson , A. Strugarek , P. Charbonneau

We aim to reproduce the structure of the corona above a solar active region as seen in the extreme ultraviolet (EUV) using a three-dimensional magnetohydrodynamic (3D MHD) model. The 3D MHD data-driven model solves the induction equation…

Solar and Stellar Astrophysics · Physics 2019-04-30 Jörn Warnecke , Hardi Peter

Context: Solar active regions (ARs) are key manifestations of the Sun's magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and…

Solar and Stellar Astrophysics · Physics 2025-08-06 M. Švanda , J. Jurčák , M. Schmassmann

Modeling the interface region between solar photosphere and corona is challenging, because the relative importance of magnetic and plasma forces change by several orders of magnitude. While the solar corona can be modeled by the force-free…

Solar and Stellar Astrophysics · Physics 2018-10-31 Xiaoshuai Zhu , Thomas Wiegelmann
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