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We present a careful assess of the forced field extrapolation using Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) magnetogram. The convergence property is checked by several metrics. The extrapolated field lines…

Solar and Stellar Astrophysics · Physics 2017-03-22 Xiaoshuai Zhu , Huaning Wang , Zhanle Du , Han He

Solar flares are explosive events in the solar corona, representing fast conversion of magnetic energy into thermal and kinetic energy, and hence radiation, due to magnetic reconnection. Modelling is essential for understanding and…

Solar and Stellar Astrophysics · Physics 2019-02-13 M. Gordovskyy , P. K. Browning , R. F. Pinto

The quality of today's research is often tightly limited to the available computing power and scalability of codes to many processors. For example, tackling the problem of heating the solar corona requires a most realistic description of…

Solar and Stellar Astrophysics · Physics 2019-08-26 Philippe-A. Bourdin

Force-free extrapolations are widely used to study the magnetic field in the solar corona based on surface measurements. The extrapolations assume that the ratio of internal energy of the plasma to magnetic energy, the plasma-beta is…

Solar and Stellar Astrophysics · Physics 2015-11-25 H. Peter , J. Warnecke , L. P. Chitta , R. H. Cameron

The SDO/HMI instruments provide photospheric vector magnetograms with a high spatial and temporal resolution. Our intention is to model the coronal magnetic field above active regions with the help of a nonlinear force-free extrapolation…

Solar and Stellar Astrophysics · Physics 2015-06-04 T. Wiegelmann , J. K. Thalmann , B. Inhester , T. Tadesse , X. Sun , J. T. Hoeksema

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs)…

Solar and Stellar Astrophysics · Physics 2017-05-09 A. Prasad , R. Bhattacharyya , Sanjay Kumar

In the quiet solar photosphere, the mixed polarity fields form a magnetic carpet, which continuously evolves due to dynamical interaction between the convective motions and magnetic field. This interplay is a viable source to heat the solar…

Solar and Stellar Astrophysics · Physics 2014-09-16 L. P. Chitta , R. Kariyappa , A. A. van Ballegooijen , E. E. DeLuca , S. K. Solanki

We present a new code designed to solve the equations of classical ideal magneto-hydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centers on the analysis of solar phenomena within…

Solar and Stellar Astrophysics · Physics 2015-10-22 J. J. Gonzalez-Aviles , A. Cruz-Osorio , F. D. Lora-Clavijo , F. S. Guzman

Knowledge regarding the coronal magnetic field is important for the understanding of many phenomena, like flares and coronal mass ejections. Because of the low plasma beta in the solar corona the coronal magnetic field is often assumed to…

Astrophysics · Physics 2008-11-26 Thomas Wiegelmann , Bernd Inhester , Takashi Sakurai

Global magnetohydrodynamic (MHD) models play an important role in the infrastructure of space weather forecasting. Validating such models commonly utilizes in situ solar wind measurements made near the orbit of the Earth. The purpose of…

Solar and Stellar Astrophysics · Physics 2024-10-31 Chin-Chun Wu , Kan Liou , Brian E. Wood , Y. M. Wang

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

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

The dynamical coupling between the solar chromospheric plasma and magnetic field is investigated by numerically solving a fully self-consistent, two-dimensional initial-value problem for the nonlinear collisional MHD equations including…

Solar and Stellar Astrophysics · Physics 2015-12-09 L. M. Alekseeva , S. P. Kshevetskii

Knowledge of the structure of the coronal magnetic field is important for our understanding of many solar activity phenomena, e.g. flares and CMEs. However, the direct measurement of coronal magnetic fields is not possible with present…

Astrophysics · Physics 2020-01-29 T. Wiegelmann , T. Neukirch

We use SDO/HMI and SOLIS/VSM photospheric magnetic field measurements to model the force-free coronal field above a solar active region, assuming magnetic forces to dominate. We take measurement uncertainties caused by, e.g., noise and the…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. K. Thalmann , A. Pietarila , X. Sun , T. Wiegelmann

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 2D local box simulations of near-surface radiative magneto-convection with prescribed magnetic flux, carried out with the MHD version of the CO5BOLD code for the Sun and a solar-like star with a metal-poor chemical composition…

Solar and Stellar Astrophysics · Physics 2009-11-13 M. Steffen , H. -G. Ludwig , O. Steiner

Context. Multi-dimensional solar flare simulations have not yet included detailed analysis of the lower atmospheric responses such as down-flowing chromospheric compressions and chromospheric evaporation processes. Aims. We present an…

Solar and Stellar Astrophysics · Physics 2024-02-02 Malcolm Druett , Wenzhi Ruan , Rony Keppens

Observations of the upper chromosphere shows an enormous amount of intricate fine structure. Much of this comes in the form of linear features which are most often assumed to be well aligned with the direction of the magnetic field in the…

Solar and Stellar Astrophysics · Physics 2017-10-23 Juan Martínez-Sykora , Bart De Pontieu , Mats Carlsson , Viggo Hansteen

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