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Solar eruptions, including flares and coronal mass ejections (CMEs), have a significant impact on Earth. Some flares are associated with CMEs, and some flares are not. The association between flares and CMEs is not always obvious. In this…

We present a long short-term memory (LSTM) network for predicting whether an active region (AR) would produce a gamma-class flare within the next 24 hours. We consider three gamma classes, namely >=M5.0 class, >=M class, and >=C class, and…

Solar and Stellar Astrophysics · Physics 2019-06-06 Hao Liu , Chang Liu , Jason T. L. Wang , Haimin Wang

With the aim of understanding how the magnetic properties of active regions (ARs) control the eruptive character of solar flares, we analyze 719 flares of Geostationary Operational Environmental Satellite (GOES) class $\geq$C5.0 during…

Solar and Stellar Astrophysics · Physics 2021-09-01 Ting Li , Anqin Chen , Yijun Hou , Astrid M. Veronig , Shuhong Yang , Jun Zhang

A statistical analysis of magnetic energies of the nonlinear force-free and potential fields, and their difference (a proxy for the free magnetic energy) in active regions (ARs) on the Sun of different Hale (Mount Wilson) and McIntosh…

Solar and Stellar Astrophysics · Physics 2025-04-15 I. V. Zimovets , I. N. Sharykin , W. -Q. Gan

It is well known that the long-term evolution of the photospheric magnetic field plays an important role in building up free energy to power solar eruptions. Observations, despite being controversial, have also revealed a rapid and…

Solar and Stellar Astrophysics · Physics 2012-09-11 Shuo Wang , Chang Liu , Rui Liu , Na Deng , Yang Liu , Haimin Wang

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

We investigated the three-dimensional (3D) magnetic structures and dynamics responsible for particle acceleration in an X7.1-class flare that occurred on October 1, 2024, in NOAA active region 13842. We combined stereoscopic hard X-ray…

Solar and Stellar Astrophysics · Physics 2026-02-11 Keitarou Matsumoto , Satoshi Inoue , Meiqi Wang , Säm Krucker , Satoshi Masuda , Muriel Zoë Stiefel , Jeongwoo Lee , Bin Chen , Haimin Wang

Solar flares are complex phenomena driven by the release of magnetic energy, but a large energy reservoir is not sufficient to determine their eruptive potential; the magnetic topology and plasma dynamics play a key role. We investigate the…

Solar and Stellar Astrophysics · Physics 2026-03-04 C. J. Díaz Baso , J. de la Cruz Rodríguez , H. -P. Doerr , M. van Noort , A. Prasad , A. Feller , D. Kiselman

Studies of vertical and interhemispheric coupling during Sudden Stratospheric Warmings (SSWs) suggest that gravity wave (GW) momentum flux divergence plays a key role in forcing the middle atmosphere, although observational validation of GW…

Space Physics · Physics 2016-07-05 R. J. deWit , R. E. Hibbins , P. J. Espy , Y. J. Orsolini , V. Limpasuvan , D. E. Kinnison

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

This work explores the impacts of magnetogram projection effects on machine learning-based solar flare forecasting models. Utilizing a methodology proposed by Falconer et al. (2016), we correct for projection effects present in Georgia…

Solar and Stellar Astrophysics · Physics 2025-02-12 Griffin T. Goodwin , Viacheslav M. Sadykov , Petrus C. Martens

Using the HMI/SDO vector magnetic field observations, we studied the relation of degree of magnetic non-potentiality with the observed flare/CME in active regions. From a sample of 77 flare/CME cases, we found a general relation that degree…

Solar and Stellar Astrophysics · Physics 2018-06-27 N. Vasantharaju , P. Vemareddy , B. Ravindra , V. H. Doddamani

Using the H$\alpha$ data from the New Vacuum Solar Telescope (NVST) at the Fuxian Solar Observatory together with multi-wavelength images and magnetograms obtained by Solar Dynamics Observatory (SDO), we study the detailed process of three…

Solar and Stellar Astrophysics · Physics 2020-01-08 Guorong Chen , Xiaoli Yan

Photospheric magnetic field not only plays important roles in building up free energy and triggering solar eruptions, but also has been observed to change rapidly and permanently responding to the coronal magnetic field restructuring due to…

Solar and Stellar Astrophysics · Physics 2011-03-02 Shuo Wang , Chang Liu , Rui Liu , Na Deng , Yang Liu , Haimin Wang

We study flare processes in the solar atmosphere using observational data for a M1-class flare of June 12, 2014, obtained by New Solar Telescope (NST/BBSO) and Helioseismic Magnetic Imager (HMI/SDO). The main goal is to understand triggers…

Solar and Stellar Astrophysics · Physics 2018-01-17 I. N. Sharykin , V. M. Sadykov , A. G. Kosovichev , S. Vargas-Dominguez , I. V. Zimovets

This paper continues the cycle of authors' works on the detection of precursors of large flares (M5 and higher classes) in active regions (ARs) of the Sun by their microwave radiation and magnetographic characteristics. Generalization of…

Solar and Stellar Astrophysics · Physics 2017-11-28 V. E. Abramov-Maximov , V. N. Borovik , L. V. Opeikina , A. G. Tlatov , L. V. Yasnov

On 7 January 2014 an X1.2 flare and CME with a radial speed $\approx$2500 km s$^{-1}$ was observed from near an active region close to disk center. This led many forecasters to estimate a rapid arrival at Earth ($\approx$36 hours) and…

Giant flares on soft gamma-ray repeaters that are thought to take place on magnetars release enormous energy in a short time interval. Their power can be explained by catastrophic instabilities occurring in the magnetic field configuration…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Y. Meng , J. Lin , L. Zhang , K. K. Reeves , Q. S. Zhang , F. Yuan

In this paper, we present the multi-wavelength study of a high level of solar activity during which a single active region produced multiple flares/CMEs. According to the sunspot observations, the current solar cycle 24 manifest to be less…

Solar and Stellar Astrophysics · Physics 2020-12-10 Shirsh Lata Soni , Manohar Lal Yadav , Radhe Syam Gupta , Pyare lal Verma

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