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Related papers: Post-flare evolution of AR 10923 with Hinode/XRT

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Magnetic flux ropes play a key role in triggering solar flares in the solar atmosphere. In this paper, we investigate the evolution of active region NOAA 12268 within 36 hours from 2015 January 29 to 30, during which a flux rope was formed…

Solar and Stellar Astrophysics · Physics 2019-06-12 Z. Zhong , Y. Guo , M. D. Ding , C. Fang , Q. Hao

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

Active regions often show S-shaped structures in the corona called sigmoids. These are highly sheared and twisted loops formed along the polarity inversion line. They are considered to be one of the best pre-eruption signatures for CMEs.…

Solar and Stellar Astrophysics · Physics 2021-03-31 Sargam M. Mulay , Durgesh Tripathi , Helen Mason

We investigated four major solar flare events that occurred in active regions NOAA 10930 (December 13 and 14, 2006) and NOAA 11158 (February 13 and 15, 2011) by using data observed by the Solar Optical Telescope (SOT) onboard the Hinode…

Solar and Stellar Astrophysics · Physics 2015-06-17 Y. Bamba , K. Kusano , T. T. Yamamoto , T. J. Okamoto

In this paper, we present a study on persistent and gradual penumbral decay and correlated decline of the photospheric transverse field component during 10-20 hours before a major flare (X1.8) eruption on 2011 September 7. This long-term…

Solar and Stellar Astrophysics · Physics 2015-10-21 Guiping Ruan , Yao Chen , Haimin Wang

We use high-resolution images of the sun obtained by the SDO/AIA instrument to study the evolution of the coronal loops in a flaring solar active region. During 15 February 2011 a X-2.2 class flare occurred in NOAA 11158, a…

Solar and Stellar Astrophysics · Physics 2015-06-04 S. Gosain

Solar flares are powered by energy stored in the coronal magnetic field, a portion of which is released when the field reconfigures into a lower energy state. Investigation of sunspot magnetic field topology during flare activity is useful…

Solar and Stellar Astrophysics · Physics 2015-03-10 Sophie A. Murray , D. Shaun Bloomfield , Peter T. Gallagher

We investigate the plasma and magnetic environment of active region NOAA 11261 on 2 August 2011 around a GOES M1.4 flare/CME (SOL2011-08-02T06:19). We compare coronal emission at (extreme) ultraviolet and X-ray wavelengths, using SDO AIA…

Solar and Stellar Astrophysics · Physics 2016-08-03 Julia K. Thalmann , Astrid M. Veronig , Yang Su

We analyze the structure and evolution of ribbons from the M7.3 SOL2014-04-18T13 flare using ultraviolet (UV) images from IRIS and SDO/AIA, magnetic data from SDO/HMI, hard X-ray (HXR) images from RHESSI, and light curves from Fermi/GBM, in…

Solar and Stellar Astrophysics · Physics 2022-03-09 Stephen J. Naus , Jiong Qiu , C. Richard DeVore , Spiro K. Antiochos , Joel T. Dahlin , James F. Drake , Marc Swisdak

During solar flares, magnetic energy can be converted into electromagnetic radiation from radio waves to $\gamma$ rays. Enhancements in the continuum at visible wavelengths give rise to white-light flares, as well as continuum enhancements…

In the standard model, magnetic reconnection at a vertical current sheet above the flare arcade is key to explaining many aspects of solar eruptions. The supra-arcade region is where the vertical current sheet is supposedly located, and…

Solar and Stellar Astrophysics · Physics 2025-12-23 Hanya Pan , Astrid M. Veronig , Rui Liu

Recently, a number of peculiar flares have been reported, which demonstrate significant non-thermal particle signatures with a low, if any, thermal emission, that implies close association of the observed emission with the primary energy…

We study the magnetic field structures of hard X-ray sources and flare ribbons of the M1.1 flare in active region NOAA 10767 on 2005 May 27. We have found in a nonlinear force-free field extrapolation, over the same polarity inversion line,…

Solar and Stellar Astrophysics · Physics 2015-06-03 Y. Guo , M. D. Ding , B. Schmieder , P. Démoulin , H. Li

We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties…

Solar and Stellar Astrophysics · Physics 2015-05-14 Pankaj Kumar , P. K. Manoharan , Wahab Uddin

Emerging flux regions (EFRs) are known to exhibit various sporadic local heating events in the lower atmosphere. To investigate the characteristics of these events, especially to link the photospheric magnetic fields and atmospheric…

Solar and Stellar Astrophysics · Physics 2017-02-15 Shin Toriumi , Yukio Katsukawa , Mark C. M. Cheung

We present the application of the data-driven branch of the MURaM code to the extensively studied flare-productive active region 11158. We refine the hybrid model strategy, which was described in the earlier paper of this series, to model…

Solar and Stellar Astrophysics · Physics 2026-04-03 Feng Chen

We present observations and analysis of an X1.8 non-eruptive solar flare on 2012 October 23, which is characterized by an extremely large late-phase peak seen in the warm coronal extreme-ultraviolet (EUV) emissions ($\sim$ 3 MK), with the…

Solar and Stellar Astrophysics · Physics 2024-10-25 Shihan Li , Yu Dai , Mingde Ding , Jinhan Guo , Hao Wu

In this paper we describe observations acquired by satellite instruments (Hinode/SOT and IRIS) and ground-based telescopes (ROSA@DST) during two consecutive C7.0 and X1.6 flares occurred in active region NOAA 12205 on 2014 November 7. The…

Solar and Stellar Astrophysics · Physics 2019-07-17 F. Zuccarello , S. L. Guglielmino , V. Capparelli , M. Mathioudakis , P. Keys , L. Fletcher , S. Criscuoli , M. Falco , M. Murabito

We present SDO/AIA observations of an eruptive X-class flare of July 12, 2012, and compare its evolution with the predictions of a 3D numerical simulation. We focus on the dynamics of flare loops that are seen to undergo slipping…

Solar and Stellar Astrophysics · Physics 2015-06-18 Jaroslav Dudík , Miho Janvier , Guillaume Aulanier , Giulio Del Zanna , Marian Karlický , Helen Mason , Brigitte Schmieder

The standard model for eruptive flares has in the past few years been extended to 3D. It predicts typical J-shaped photospheric footprints of the coronal current layer, forming at similar locations as the Quasi-Separatrix Layers (QSLs).…

Solar and Stellar Astrophysics · Physics 2016-10-04 M. Janvier , A. Savcheva , E. Pariat , S. Tassev , S. Millholland , V. Bommier , P. McCauley , S. McKillop , F. Dougan