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Solar flares and coronal mass ejections are associated with rapid changes in field connectivity and powered by the partial dissipation of electrical currents in the solar atmosphere. A critical unanswered question is whether the currents…

The emergence of active regions on the Sun is an integral feature of the solar dynamo mechanism. However, details about the generation of active-region-scale magnetism and the journey of this magnetic flux to the photosphere are still in…

Solar and Stellar Astrophysics · Physics 2023-06-13 Maria A. Weber , Hannah Schunker , Laurène Jouve , Emre Işık

Radiative magnetohydrodynamic simulation includes sufficiently realistic physics to allow for the synthesis of remote sensing observables that can be quantitatively compared with observations. We analyze the largest flare in a simulation of…

Solar and Stellar Astrophysics · Physics 2023-06-28 Feng Chen , Matthias Rempel , Yuhong Fan

We used multi-wavelength high-resolution data from ARIES, THEMIS, and SDO instruments, to analyze a non-standard, C3.3 class flare produced within the active region NOAA 11589 on 2012 October 16. Magnetic flux emergence and cancellation…

Solar and Stellar Astrophysics · Physics 2016-02-22 K. Dalmasse , R. Chandra , B. Schmieder , G. Aulanier

Magnetic flux emergence and decay in the Sun span from days to months. However, their tracking is typically limited to about half a solar rotation when relying on single-vantage-point observations. Combining observations from both the…

Solar and Stellar Astrophysics · Physics 2026-01-14 I. Kontogiannis , Y. Zhu , K. Barczynski , M. Z. Stiefel , H. Collier , J. McKevitt , J. S. Castellanos Durán , S. Berdyugina , L. K. Harra

During eruptive flares, vector magnetograms show increasing horizontal magnetic field and downward Lorentz force in the Sun's photosphere around the polarity-inversion line. Such behavior has often been associated with the implosion…

Solar and Stellar Astrophysics · Physics 2019-06-05 Krzysztof Barczynski , Guillaume Aulanier , Sophie Masson , Michael S. Wheatland

A current sheet, where magnetic energy is liberated through reconnection and is converted to other forms, is thought to play the central role in solar flares, the most intense explosions in the heliosphere. However, the evolution of a…

Solar and Stellar Astrophysics · Physics 2021-04-28 L. P. Chitta , E. R. Priest , X. Cheng

Magnetic flux generated and intensified by the solar dynamo emerges into the solar atmosphere, forming active regions (ARs) including sunspots. Existing theories of flux emergence suggest that the magnetic flux can rise buoyantly through…

Solar and Stellar Astrophysics · Physics 2020-06-17 Aiying Duan , Chaowei Jiang , Shin Toriumi , Petros Syntelis

The dynamics of magnetic fields in the Sun's active regions plays a key role in triggering solar eruptions. Studies have shown that changes in the photosphere's magnetic field can destabilize large-scale structure of the corona, leading to…

Solar and Stellar Astrophysics · Physics 2025-03-25 Partha Chowdhury , Belur Ravindra , Sanjiv Kumar Tiwari

Large scale solar eruptions significantly impact space weather and damages space-based human infrastructures. It is necessary to predict large scale solar eruptions, which will enable us to protect our vulnerable infrastructures of modern…

Solar and Stellar Astrophysics · Physics 2020-07-08 Soumitra Hazra , Gopal Sardar , Partha Choudhuri

The sudden release of magnetic energy on the Sun drives powerful solar flares and coronal mass ejections. The key issue is the difficulty in predicting the occurrence time and location of strong solar eruptions, i.e., those leading to the…

Solar eruptions are the most powerful drivers of space weather. To understand their cause and nature, it is crucial to know how the coronal magnetic field evolves before eruption. Here we study the formation process of a relatively…

Solar and Stellar Astrophysics · Physics 2020-03-25 Wen He , Chaowei Jiang , Peng Zou , Aiying Duan , Xueshang Feng , Pingbing Zuo , Yi Wang

Erupting magnetic flux ropes (MFRs) play a crucial role in producing solar flares. However, the formation of erupting MFRs in complex coronal magnetic configurations and their subsequent evolution in the flaring events are not fully…

Solar and Stellar Astrophysics · Physics 2023-08-30 Avijeet Prasad , Sanjay Kumar , Alphonse C. Sterling , Ronald L. Moore , Guillaume Aulanier , R. Bhattacharyya , Qiang Hu

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

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

Solar active regions (ARs) that produce major flares typically exhibit strong plasma shear flows around photospheric magnetic polarity inversion lines (MPILs). It is therefore important to quantitatively measure such photospheric shear…

Solar and Stellar Astrophysics · Physics 2018-10-29 Sung-Hong Park , Jordan A. Guerra , Peter T. Gallagher , Manolis K. Georgoulis , D. Shaun Bloomfield

The physical conditions that determine whether or not solar active regions (ARs) produce strong flares and coronal mass ejections (CMEs) are not yet well understood. Here we investigate the association between electric-current…

Solar and Stellar Astrophysics · Physics 2017-09-06 Yang Liu , Xudong Sun , Tibor Török , Viacheslav S. Titov , James E. Leake

Coronal mass ejections (CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere into the solar wind.…

Solar and Stellar Astrophysics · Physics 2017-07-13 X. Cheng , Y. Guo , M. D. Ding

In this paper, we present a comprehensive study of the evolutionary phases of a major M6.6 long duration event (LDE) with special emphasize on its pre-flare phase. The event occurred in NOAA 12371 on 2015 June 22. A remarkable aspect of the…

Solar and Stellar Astrophysics · Physics 2020-07-22 Suraj Sahu , Bhuwan Joshi , Prabir K. Mitra , Astrid M. Veronig , V. Yurchyshyn

We present a detailed investigation on the evolution of observed net vertical current using a time series of vector magnetograms of the active region (AR) NOAA 11158 obtained from Helioseismic Magnetic Imager. We also discuss the relation…

Solar and Stellar Astrophysics · Physics 2015-09-16 P. Vemareddy , P. Venkatakrishnan , S. Karthikreddy