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The formation of the MFRs in the pre-flare stage, and how this leads to coronal rain in a post-eruption magnetic loop is not fully understood. We explore the formation, and eruption of MFRs, followed by the appearance of coronal rain in the…

Solar and Stellar Astrophysics · Physics 2024-08-07 Samrat Sen , Avijeet Prasad , Valeriia Liakh , Rony Keppens

We study the magnetic structure of successively erupting sigmoid in active region 12371 by modeling the quasi-static coronal field evolution with non-linear force-free field (NLFFF) equilibria. HMI/SDO vector magnetograms are used as input…

Solar and Stellar Astrophysics · Physics 2018-05-02 P. Vemareddy , P. Demóulin

It remains unclear how solar flares are triggered and in what conditions they can be eruptive with coronal mass ejections. Magnetic flux ropes (MFRs) has been suggested as the central magnetic structure of solar eruptions, and their ideal…

Solar and Stellar Astrophysics · Physics 2021-03-17 Aiying Duan , Chaowei Jiang , Zhenjun Zhou , Xueshang Feng , Jun Cui

In this work we describe a numerical optimization method for computing stationary MHD-equilibria. The newly developed code is based on a nonlinear force-free optimization principle. We apply our code to model the solar corona using synoptic…

Solar and Stellar Astrophysics · Physics 2020-11-11 Thomas Wiegelmann , Thomas Neukirch , Dieter H. Nickeler , Iulia Chifu

Magnetic flux ropes (MFRs) rising buoyantly through the Sun's convection zone are thought to be subject to viscous forces preventing them from rising coherently. Numerous studies have suggested that MFRs require a minimum twist in order to…

Solar and Stellar Astrophysics · Physics 2021-01-27 Kalman J. Knizhnik , James E. Leake , Mark G. Linton , Sally Dacie

Magnetograms acquired with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) were used to calculate and analyze time variations of turbulence and multifractality in the photosphere during the…

Solar and Stellar Astrophysics · Physics 2025-06-04 Valentina Abramenko

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

This work analyzes the Hall magnetohydrodynamics (HMHD) and magnetohydrodynamics (MHD) numerical simulations of a flaring solar active region as a testbed while idealizing the coronal Alfv\'en speed to be of two orders of magnitude lesser.…

Solar and Stellar Astrophysics · Physics 2022-02-16 Kamlesh Bora , Ramit Bhattacharyya , Avijeet Prasad , Bhuwan Joshi , Qiang Hu

Currently, achieving a balance between computational efficiency, accuracy, and numerical stability in CME simulations, particularly in the sub-Alfv{'e}nic coronal region, remains a significant challenge. This paper aims to address the…

The rapid, irreversible change of the photospheric magnetic field has been recognized as an important element of the solar flare process. This Letter reports such a rapid change of magnetic fields during the 2011 February 13 M6.6 flare in…

Solar and Stellar Astrophysics · Physics 2015-06-03 Chang Liu , Na Deng , Rui Liu , Jeongwoo Lee , Thomas Wiegelmann , Ju Jing , Yan Xu , Shuo Wang , Haimin Wang

We have performed a three-dimensional magnetohydrodynamic simulation to study the emergence of a twisted magnetic flux tube from -20,000 km of the solar convection zone to the corona through the photosphere and the chromosphere. The middle…

Solar and Stellar Astrophysics · Physics 2015-06-03 S. Toriumi , T. Yokoyama

Solar flares and coronal mass ejections (CMEs) are among the most energetic events in the solar system, impacting the near-Earth environment. Flare productivity is empirically known to be correlated with the size and complexity of active…

Solar and Stellar Astrophysics · Physics 2017-06-16 Chloé Guennou , Etienne Pariat , Nicole Vilmer , James E. Leake

The theoretical concept that braided magnetic field lines in the solar corona may dissipate a sufficient amount of energy to account for the brightening observed in the active-region corona, has been substantiated by high-resolution…

Solar and Stellar Astrophysics · Physics 2015-06-17 J. K. Thalmann , S. K. Tiwari , T. Wiegelmann

Filaments are special plasma phenomena embedded in the solar atmosphere, characterized by unique thermodynamic properties and magnetic structures. Magnetohydrodynamic (MHD) simulations are useful to investigate the eruption mechanisms of…

Solar and Stellar Astrophysics · Physics 2025-04-22 Yihua Li , Yang Guo , Jinhan Guo , M. D. Ding , Chun Xia , Rony Keppens

We analyze the complete chain of effects caused by a solar eruptive event in order to better understand the dynamic evolution of magnetic-field related quantities in interplanetary space, in particular that of magnetic flux and helicity. We…

Solar and Stellar Astrophysics · Physics 2023-01-11 J. K. Thalmann , M. Dumbovic , K. Dissauer , T. Podladchikova , G. Chikunova , M. Temmer , E. Dickson , A. M. Veronig

Measurements of the interplanetary magnetic field (IMF) over several solar cycles do not agree with computed values of open magnetic flux from potential field extrapolations. The discrepancy becomes greater around solar maximum in each…

Solar and Stellar Astrophysics · Physics 2015-05-19 A. R. Yeates , D. H. Mackay , A. A. van Ballegooijen , J. A. Constable

The data behavior of the pion-photon transition form factor (TFF) is discussed using a nonlinear mathematical model with two parameters $B$ and $C$. Analysis shows that the model's inherent inhibition provides a precondition for the…

High Energy Physics - Phenomenology · Physics 2025-06-11 N. G. Stefanis

We present an investigation of an eruption event of coronal mass ejection (CME) magnetic flux rope (MFR) from source active region (AR) NOAA 11719 on 11 April 2013 utilizing observations from SDO, STEREO, SOHO, and WIND spacecraft. The…

Solar and Stellar Astrophysics · Physics 2015-10-08 P. Vemareddy , W. Mishra

In this study, photospheric vector magnetograms obtained with the Synoptic Optical Long-term Investigations of the Sun survey (SOLIS), are used as boundary conditions to model the three-dimensional nonlinear force-free (NLFF) coronal…

Solar and Stellar Astrophysics · Physics 2015-05-30 Tilaye Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

We present results from 3D magnetohydrodynamic (MHD) simulations of the emergence of a twisted convection zone flux tube into a pre-existing coronal dipole field. As in previous simulations, following the partial emergence of the…

Solar and Stellar Astrophysics · Physics 2015-06-18 J. E. Leake , M. G. Linton , S. K. Antiochos
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