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Related papers: MHD consistent cellular automata (CA) models I: Ba…

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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

Active regions (ARs) are typical magnetic structures found in the solar atmosphere. We calculate several magnetohydrostatic (MHS) equilibrium models that include the effect of a finite plasma-$\beta$ and gravity and that are representative…

Solar and Stellar Astrophysics · Physics 2023-03-08 Jaume Terradas , Thomas Neukirch

Many questions must be answered before understanding the relationship between the emerging magnetic flux through the solar surface and the extreme geoeffective events. The main ingredients for getting X-ray class flares and large…

Solar and Stellar Astrophysics · Physics 2025-09-22 Brigitte Schmieder , Jinhan Guo , Guillaume Aulanier , Anwesha Maharana , Stefaan Poedts

A model for the solar coronal magnetic field is proposed where multiple directed loops evolve in space and time. Loops injected at small scales are anchored by footpoints of opposite polarity moving randomly on a surface. Nearby footpoints…

Statistical Mechanics · Physics 2009-11-07 D. Hughes , M. Paczuski , R. O. Dendy , P. Helander , K. G. McClements

Scale invariance is a hallmark of many natural systems, including solar flares, where energy release spans a vast range of scales. Recent computational advances, at the level of both algorithmics and hardware, have enabled high-resolution…

The chapter "Solar Active Region Electric Currents Before and During Eruptive Flares" is a discussion on electric currents in the pre-eruption state and in the course of eruptions of solar magnetic structures, using information from solar…

Solar and Stellar Astrophysics · Physics 2019-03-13 Brigitte Schmieder , Guillaume Aulanier

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

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 study a 2D cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their…

Solar and Stellar Astrophysics · Physics 2017-03-22 Marcelo López Fuentes , James A. Klimchuk

An accepted model for magnetospheric substorms is proposed as the basis for a generic model for magnetic explosions, and is applied to solar flares. The model involves widely separated energy-release and particle-acceleration regions, with…

Solar and Stellar Astrophysics · Physics 2015-06-04 D. B. Melrose

The characterization of global energy storage and release in the coupled solar wind-magnetosphere system remains one of the fundamental problems of space physics.Recently, it has been realised that a new paradigm in physics, that of Self…

Astrophysics · Physics 2021-04-28 Sandra Chapman , Nicholas Watkins

We have developed 3D, compressible, non-linear radiative MHD simulations to study the influence of the magnetic field of various strength and geometry on the turbulent convective cells and on the excitation mechanisms of the acoustic…

Solar and Stellar Astrophysics · Physics 2009-01-29 Irina Kitiashvili , Laetitia Jacoutot , Alexander Kosovichev , Alan Wray , Nagi Mansour

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

Cellular automata (CAs) are fully-discrete dynamical models that have received much attention due to the fact that their relatively simple setup can nonetheless express highly complex phenomena. Despite the model's theoretical maturity and…

Cellular Automata and Lattice Gases · Physics 2025-07-10 Michiel Rollier , Kallil M. C. Zielinski , Aisling J. Daly , Odemir M. Bruno , Jan M. Baetens

Cellular automaton (CA) approach is an important theoretical framework for studying complex system behavior and has been widely applied in various research field. CA traffic flow models have the advantage of flexible evolution rules and…

Cellular Automata and Lattice Gases · Physics 2018-10-09 Junfang Tian , Chenqiang Zhu , Rui Jiang

Magnetic clouds (MCs) are "magnetized plasma clouds" moving in the solar wind. MCs transport magnetic flux and helicity away from the Sun. These structures are not stationary but feature temporal evolution as they propagate in the solar…

Solar and Stellar Astrophysics · Physics 2015-05-30 G. Dalakishvili , J. Kleimann , H. Fichtner , S. Poedts

Solar energetic events are caused by the release of magnetic energy accumulated in the solar atmosphere. To understand their initiating physical mechanisms, the dynamics of the coronal magnetic fields must be studied. Unfortunately, the…

Solar and Stellar Astrophysics · Physics 2024-08-14 Yeongmin Kang , Takafumi Kaneko , K. D. Leka , Kanya Kusano

We propose a new model for the initiation of a solar coronal mass ejection (CME). The model agrees with two properties of CMEs and eruptive flares that have proved to be very difficult to explain with previous models. a) Very low-lying…

Astrophysics · Physics 2009-10-30 S. K. Antiochos , C. R. DeVore , J. A. Klimchuk

Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare…

Solar and Stellar Astrophysics · Physics 2017-01-11 Shin Toriumi , Carolus J. Schrijver , Louise K. Harra , Hugh Hudson , Kaori Nagashima

We present a reduced magnetohydrodynamic (MHD) mathematical model describing the dynamical behavior of highly conducting plasmas with frozen-in magnetic fields, constrained by the assumption that, there exists a frame of reference, where…

Plasma Physics · Physics 2022-02-23 Igor V Sokolov , Lulu Zhao , Tamas I Gombosi