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Magnetic flux ropes (MFRs) are fundamental magnetic structures in solar eruptions, whose formation is generally attributed to (1) the emergence of subsurface flux tubes or (2) flux cancellation driven by photospheric horizontal flows and…

Solar and Stellar Astrophysics · Physics 2025-12-17 Can Wang , Takaaki Yokoyama , Feng Chen , Chen Xing , Mingde Ding , Zekun Lu

Solar eruptive activities could occur in weak magnetic field environments and over large spatial scales, especially relevant to eruptions involving intermediate or quiescent solar filaments. To handle the large scales, we implement and…

Solar and Stellar Astrophysics · Physics 2023-09-06 Yang Guo , Jinhan Guo , Yiwei Ni , M. D. Ding , P. F. Chen , Chun Xia , Rony Keppens , Kai E. Yang

Using solar wind observation near PSP perihelions as constraints, we have investigated the parameters in various PFSS model methods. It's found that the interplanetary magnetic field extrapolation with source surface height $R_\mathrm{SS} =…

Solar and Stellar Astrophysics · Physics 2023-05-23 Yuechun Song

Self-organization in continuous systems is associated with dissipative processes. In particular, for magnetized plasmas, it is known as magnetic relaxation, where the magnetic energy is converted into heat and kinetic energy of flow through…

Solar and Stellar Astrophysics · Physics 2024-01-23 Satyam Agarwal , Ramit Bhattacharyya , Shangbin Yang

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

Context. Some of the most dynamic active regions are associated with complex photospheric magnetic configurations such as quadrupolar regions, and especially ones with a $\delta$-spot configuration and a strong Polarity Inversion Line…

Solar and Stellar Astrophysics · Physics 2019-10-09 P. Syntelis , E. J. Lee , C. W. Fairbairn , V. Archontis , A. W. Hood

We present a magnetic flux rope (FR) extraction tool for solar coronal magnetic field modelling data, which builds upon the methodology from Wagner et al. (2023). We apply the scheme to magnetic field simulations of active regions AR12473…

On SOL2017-09-06 solar active region 12673 produced an X9.3 flare which is regarded as largest to occur in solar cycle 24. In this work we have preformed a magnetohydrodynamic (MHD) simulation in order to reveal the three-dimensional (3D)…

Solar and Stellar Astrophysics · Physics 2018-11-07 Satoshi Inoue , Daikou Shiota , Yumi Bamba , Sung-Hong Park

It is widely believed that loops observed in the solar atmosphere trace out magnetic field lines. However, the degree to which magnetic field extrapolations yield field lines that actually do follow loops has yet to be studied…

Solar and Stellar Astrophysics · Physics 2018-06-27 Harry P. Warren , Nicholas A. Crump , Ignacio Ugarte-Urra , Xudong Sun , Markus J. Aschwanden , Thomas Wiegelmann

Solar flare simulations are commonly initialised using non-linear force free field (NLFF) extrapolations derived from photospheric vector magnetograms. However, the force free assumption neglects plasma forces and may limit the available…

Solar and Stellar Astrophysics · Physics 2026-05-15 W. Bate , M. Gordovskyy , A. Prasad , A. S. Brun , A. Strugarek , M. V. Sieyra , P. Browning , S. Inoue , K. Matsumoto , A. Roddanavar

We performed two data-based magnetohydrodynamic (MHD) simulations for solar active region 12371 which produced an M6.5 flare. The first simulation is a full data-driven simulation where the initial condition is given by a nonlinear…

Solar and Stellar Astrophysics · Physics 2023-03-01 Satoshi Inoue , Keiji Hayashi , Takahiro Miyoshi , Ju Jing , Haimin Wang

Three-dimensional magnetic topology of solar flare plays a crucial role in understanding its explosive release of magnetic energy in the corona. However, such three-dimensional coronal magnetic field is still elusive in direct observation.…

Solar and Stellar Astrophysics · Physics 2018-02-09 Chaowei Jiang , Peng Zou , Xueshang Feng , Qiang Hu , Aiying Duan , Pingbing Zuo , Yi Wang , Fengsi Wei

Magnetic-field reconnection is believed to play a fundamental role in magnetized plasma systems throughout the Universe1, including planetary magnetospheres, magnetars and accretion disks around black holes. This letter present extreme…

Solar and Stellar Astrophysics · Physics 2015-02-06 Yang Su , Astrid M. Veronig , Gordon D. Holman , Brian R. Dennis , Tongjiang Wang , Manuela Temmer , Weiqun Gan

Solar flares are intense bursts of electromagnetic radiation, which occur due to a rapid destabilization and reconnection of the magnetic field. While pre-flare signatures and trends have been investigated from magnetic observations prior…

Solar and Stellar Astrophysics · Physics 2025-06-18 Kara L. Kniezewski , Emily I. Mason , Daniel J. Emmons , Kyle E. Fitch , Seth H. Garland

Solar activity can be witnessed in the form of sunspots and active regions, where the magnetic field is enhanced by up to a factor 1000 as compared to that of the quiet Sun. In addition, solar activity manifests itself in terms of flares,…

Solar and Stellar Astrophysics · Physics 2025-07-25 Gottfried Mann , Frédéric Schuller

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

In the solar corona, magnetic helicity slowly and continuously accumulates in response to plasma flows tangential to the photosphere and magnetic flux emergence through it. Analyzing this transfer of magnetic helicity is key for identifying…

Solar and Stellar Astrophysics · Physics 2018-01-31 K. Dalmasse , E. Pariat , G. Valori , J. Jing , P. Démoulin

Context. Observations of many active regions show a slow systematic outflow/upflow from their edges lasting from hours to days. At present no physical explanation has been proven, while several suggestions have been put forward. Aims. This…

Solar and Stellar Astrophysics · Physics 2021-08-25 K. Galsgaard , M. S. Madjarska , K. Vanninathan , Z. Huang , M. Presmann

The solar active region (AR) 12192 was one of the most flare productive region of solar cycle 24, which produced many X-class flares; the most energetic being an X3.1 flare on October 24, 2014 at 21:10 UT. Customarily, such events are…

Solar and Stellar Astrophysics · Physics 2019-01-30 A. Prasad , R. Bhattacharyya , Q. Hu , S. S. Nayak , Sanjay Kumar

Extrapolation codes in Cartesian geometry for modelling the magnetic field in the corona do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, e.g., a single active region. We compare…

Solar and Stellar Astrophysics · Physics 2015-06-11 Tilaye Tadesse , T. Wiegelmann , B. Inhester , P. MacNeice , A. Pevtsov , X. Sun