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Related papers: Three-dimensional solar active region magnetohydro…

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Here we review the recent progress made in the detection, examination, characterisation and interpretation of oscillations manifesting in small-scale magnetic elements in the solar photosphere. This region of the Sun's atmosphere is…

Solar and Stellar Astrophysics · Physics 2016-03-09 David B. Jess , Gary Verth

The emergence and magnetic evolution of solar active regions (ARs) of beta-gamma-delta type, which are known to be highly flare-productive, were studied with the SOHO/MDI data in Cycle 23. We selected 31 ARs that can be observed from their…

Solar and Stellar Astrophysics · Physics 2015-08-19 Kan Takizawa , Reizaburo Kitai

The evolution of magnetic helicity has a close relationship with solar eruptions and is of interest as a predictive diagnostic. In this case study, we analyse the evolution of the normalised emergence, shearing and total magnetic helicity…

Solar and Stellar Astrophysics · Physics 2020-07-15 M. B. Korsos , P. Romano , H. Morgan , Y. Ye , R. Erdelyi , F. Zuccarello

We take a broad look at the problem of identifying the magnetic solar causes of space weather. With the lackluster performance of extrapolations based upon magnetic field measurements in the photosphere, we identify a region in the near UV…

We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general…

Astrophysics · Physics 2009-11-13 M. K. Georgoulis , Barry J. LaBonte

Solar prominences represent large-scale condensations suspended against gravity within the solar atmosphere. The Rayleigh-Taylor (RT) instability is proposed to be one of the important fundamental processes leading to the generation of…

Solar and Stellar Astrophysics · Physics 2023-04-19 Madhurjya Changmai , Jack M. Jenkins , J. -B. Durrive , Rony Keppens

We analyze a three-dimensional (3D) magnetic structure and its stability in large solar active region(AR) 12192, using the 3D coronal magnetic field constructed under a nonlinear force-free field (NLFFF) approximation. In particular, we…

Solar and Stellar Astrophysics · Physics 2016-03-09 S. Inoue , K. Hayashi , K. Kusano

Combined tearing-thermal evolution plays an important role in the disruption of current sheets, and formation of cool condensations within the solar atmosphere. However, this has received limited attention to date. We numerically explore a…

Solar and Stellar Astrophysics · Physics 2023-10-18 Samrat Sen , Jack Jenkins , Rony Keppens

Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron…

High Energy Astrophysical Phenomena · Physics 2021-08-04 Matteo Bugli , Jérôme Guilet , Martin Obergaulinger

Active regions (AR) appearing on the surface of the Sun are classified into $\alpha$, $\beta$, $\gamma$, and $\delta$ by the rules of the Mount Wilson Observatory, California on the basis of their topological complexity. Amongst these, the…

Solar and Stellar Astrophysics · Physics 2016-03-09 Piyali Chatterjee , Viggo Hansteen , Mats Carlsson

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 studied the low-frequency $\lesssim 0.5\;$h$^{-1}$ (long-period $\gtrsim 2\;$h) oscillations of active regions (ARs). The investigation is based on an analysis of a time series built from Solar Dynamics Observatory/Helioseismic and…

Solar and Stellar Astrophysics · Physics 2022-03-22 G. Dumbadze , B. M. Shergelashvili , S. Poedts , T. V. Zaqarashvili , M. Khodachenko , P. De Causmaecker

Barred galaxies are known to possess magnetic fields that may affect the properties of bar substructures such as dust lanes and nuclear rings. We use two-dimensional high-resolution magnetohydrodynamic (MHD) simulations to investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Woong-Tae Kim , James M. Stone

Typical solar flares display two quasi-parallel, bright ribbons on the chromosphere. In between is the polarity inversion line (PIL) separating concentrated magnetic fluxes of opposite polarity in active regions (ARs). Intriguingly a series…

Solar and Stellar Astrophysics · Physics 2016-09-30 Rui Liu , Jun Chen , Yuming Wang , Kai Liu

Two-dimensional (2D) materials can host stable, long-range magnetic phases in the presence of underlying magnetic anisotropy. The ability to realize the full potential of 2D magnets necessitates systematic investigation of the role of…

Context: During solar flares a large number of charged particles are accelerated to high energies, but the exact mechanism responsible for this is, so far, still unclear. Acceleration in collapsing magnetic traps is one of the mechanisms…

Solar and Stellar Astrophysics · Physics 2009-10-22 Keith J. Grady , Thomas Neukirch

We present the results of three-dimensional global magnetohydrodynamic (MHD) simulations of the Parker-shearing instability in a differentially rotating torus initially threaded by toroidal magnetic fields. An equilibrium model of…

Astrophysics · Physics 2009-10-31 M. Machida , MITSURU R. Hayashi , R. Matsumoto

Electric currents in solar active regions are thought to provide the energy released via magnetic reconnection in solar flares. Vertical electric current densities $J_z$ at the photosphere may be estimated from vector magnetogram data,…

Solar and Stellar Astrophysics · Physics 2015-06-24 M. S. Wheatland

In this paper, we investigate the ideal magnetohydrodynamics (MHD) equations on tours $\TTT^d$. For $d=3$, we resolve the flexible part of Onsager-type conjecture for Els\"{a}sser energies of the ideal MHD equations. More precisely, for…

Analysis of PDEs · Mathematics 2025-04-09 Changxing Miao , Yao Nie , Weikui Ye

Over the last decades, realistic 3D radiative-MHD simulations have become the dominant theoretical tool for understanding the complex interactions between the plasma and the magnetic field on the Sun. Most of such simulations are based on…

Solar and Stellar Astrophysics · Physics 2018-10-17 E. Khomenko , N. Vitas , M. Collados , A. de Vicente