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Aims. We investigate the configuration of a complex flux rope above a {\delta} sunspot region in NOAA AR 11515, and its eruptive expansion during a confined M5.3-class flare. Methods. We study the formation of the {\delta} sunspot using…

Solar and Stellar Astrophysics · Physics 2021-04-21 Lijuan Liu , Jiajia Liu , Jun Chen , Yuming Wang , Guoqiang Wang , Zhenjun Zhou , Jun Cui

Using multi-wavelength observation from SDO and STEREO, we investigated the mechanism of two successive eruptions (F1 & F2) of a filament in active region NOAA 11444 on 27 march, 2012. The filament was inverse `J' shaped and lying along a…

Solar and Stellar Astrophysics · Physics 2017-10-11 Sajal Kumar Dhara , Ravindra B. , Pankaj Kumar , Ravinder Kumar Banyal , Shibu K. Mathew , Bhuwan Joshi

We report a solar jet phenomenon associated with successive flares on November 10th 2014. These explosive events were involved with the satellite spots' emergence around a delta-type sunspot in the decaying active region NOAA 12205. The…

Solar and Stellar Astrophysics · Physics 2017-10-11 Takahito Sakaue , Akiko Tei , Ayumi Asai , Satoru Ueno , Kiyoshi Ichimoto , Kazunari Shibata

On June 17, 2012, we observed the evolution of a C-class flare associated with the eruption of a filament near a large sunspot in the active region NOAA 11504. We obtained high spatial resolution filtergrams using the 1.6 m New Solar…

Solar and Stellar Astrophysics · Physics 2015-06-22 Zhicheng Zeng , Jiong Qiu , Wenda Cao , Philip G. Judge

In this Letter, we give a detailed analysis to the M3.3 class flare that occurred on August 17, 2013 (SOL2013-08-17T18:16). It presents a clear picture of mutual magnetic interaction initially from the photosphere to the corona via the…

Solar and Stellar Astrophysics · Physics 2022-07-20 Yanjie Zhang , Zhe Xu , Qingmin Zhang , Jun Dai , Haisheng Ji

Recent observations in extreme-ultraviolet (EUV) wavelengths reveal an EUV late phase in some solar flares, which is characterized by a second peak in the warm coronal emissions (about 3 MK) occurring several tens of minutes to a few hours…

Solar and Stellar Astrophysics · Physics 2023-07-19 Yuehong Chen , Yu Dai , Mingde Ding

We present the study of three homologous solar eruptions from NOAA active region (AR) 11429 over four days. This large and complex AR divided into two relatively simple sub-regions: northeast (NE) and southwest (SW). Recurrent eruptions…

Solar and Stellar Astrophysics · Physics 2020-09-30 Suman K. Dhakal , Jie Zhang , Panditi Vemareddy , Nishu Karna

We have observed formation of penumbrae on a pore in the active region NOAA10838 using Dunn Solar Telescope at NSO,Sunpot,USA. Simultaneous observations using different instruments (DLSP,UBF,Gband and CaK) provide us with vector magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-20 Sreejith Padinhatteeri , Sankarasubramanian K

Fan-spine is a special topology in solar atmosphere and is closely related to magnetic null point as well as circular-ribbon flares, which can provide important information for understanding the intrinsic three-dimensional (3D) nature of…

Solar and Stellar Astrophysics · Physics 2019-01-23 Yijun Hou , Ting Li , Shuhong Yang , Jun Zhang

Solar active regions and the processes that occur in them have been extensively studied and analyzed and many types of models and characterizations have been proposed for the occurrence of different eruptive events that take place in the…

Solar and Stellar Astrophysics · Physics 2020-12-09 N. Granados Hernández , S. Vargas Domínguez

We analyze multi-wavelength data of a M7.9/1N class solar flare which occurred on 27 April, 2006 from AR NOAA 10875. GOES soft X-ray images provide the most likely signature of two interacting loops and their reconnection, which triggers…

Solar and Stellar Astrophysics · Physics 2015-05-19 Pankaj Kumar , A. K. Srivastava , B. V. Somov , P. K. Manoharan , R. Erdelyi , Wahab Uddin

Flare productivity varies among solar active regions (ARs). This study analyzed 20 ARs of contrasting sunspot areas and flare productivities to understand the super flare productivity of certain ARs. We used the flare index (FI) as an…

Solar and Stellar Astrophysics · Physics 2023-12-27 Suman K. Dhakal , Jie Zhang

We establish the largest eruptive/confined flare database to date and analyze 322 flares of \emph{GOES} class M1.0 and larger that occurred during 2010$-$2019, i.e., almost spanning the entire solar cycle 24. We find that the total unsigned…

Solar and Stellar Astrophysics · Physics 2020-08-31 Ting Li , Yijun Hou , Shuhong Yang , Jun Zhang , Lijuan Liu , Astrid M. Veronig

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 extreme space weather conditions resulting from high energetic events likes solar flares and Coronal Mass Ejections (CMEs) demand for reliable space weather forecasting. The magnetic flux tubes while rising through the convection zone…

Solar and Stellar Astrophysics · Physics 2022-10-19 B Lekshmi , Kiran Jain , Rudolf W. Komm , Dibyendu Nandy

Coronal dimmings are transient depletions of coronal plasma observed in extreme ultraviolet and soft X-rays, interpreted as low-corona signatures of coronal mass ejections (CMEs). Their evolution is closely linked to CME dynamics, flare…

Solar and Stellar Astrophysics · Physics 2026-03-26 Amaia Razquin , Karin Dissauer , Astrid M. Veronig , Graham Barnes

Active region NOAA 13842 produced two successive solar flares: an X7.1-class flare on October 1, 2024, and an X9.0-class flare on October 3, 2024. This study continues our previous simulation work that successfully reproduced the X7.1-class…

Solar and Stellar Astrophysics · Physics 2025-09-22 Keitarou Matsumoto , Satoshi Inoue , Keiji Hayashi , Nian Liu , Ying Wang , Jeongwoo Lee , Ju Jing , Haimin Wang

We observed two surges in H-alpha from the super-active region NOAA 10484. The first surge was associated with an SF/C4.3 class flare. The second one was a major surge associated with a SF/C3.9 flare. This surge was also observed with…

Solar and Stellar Astrophysics · Physics 2015-05-13 W. Uddin , P. Kumar , A. K. Srivastava , R. Chandra

We present the results of a detailed analysis of multi-wavelength observations of a very impulsive solar flare 1B/M6.7, which occurred on 10 March, 2001 in NOAA AR 9368 (N27 W42). The observations show that the flare is very impulsive with…

We study photospheric and sub-photospheric properties of active and quiet regions observed during 11-17 February 2011 including the first X-class flare X2.2 of the solar cycle 24 which occurred in the active region NOAA 11158 on 15 February…

Solar and Stellar Astrophysics · Physics 2013-10-25 R. A. Maurya