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Adverse space weather effects can often be traced to solar flares, prediction of which has drawn significant research interests. The Helioseismic and Magnetic Imager (HMI) produces full-disk vector magnetograms with continuous high cadence,…

Solar and Stellar Astrophysics · Physics 2017-07-26 Chang Liu , Na Deng , Jason T. L. Wang , Haimin Wang

In this work we study the correlation between the soft (1.6--12.4 keV, mostly thermal) and the hard (20--40 and 60--80 keV, mostly non-thermal) X-ray emission in solar flares up to the most energetic events, spanning about 4 orders of…

Astrophysics · Physics 2009-11-13 C. Isola , F. Favata , G. Micela , H. S. Hudson

Since the launch of the Solar Dynamics Observatory (SDO) in 2010 and throughout the solar cycle 24, the Sun has produced few tens of xclass flares, which are the most energetic solar events. Those flares are produced in regions where the…

Solar and Stellar Astrophysics · Physics 2024-10-23 R. L. Edgar , S. Regnier

Of all the activity observed on the Sun, two of the most energetic events are flares and Coronal Mass Ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true (Yashiro et…

Solar and Stellar Astrophysics · Physics 2016-04-25 Monica G. Bobra , Stathis Ilonidis

Based on a sample of 1114 flares observed simultaneously in hard X-rays (HXR) by the BATSE instrument and in soft X-rays (SXR) by GOES, we studied several aspects of the Neupert effect and its interpretation in the frame of the…

Astrophysics · Physics 2009-11-07 A. Veronig , B. Vrsnak , B. R. Dennis , M. Temmer , A. Hanslmeier , J. Magdalenic

The ratio of the Fe abundance in the photosphere to that in coronal flare plasmas is determined by X-ray lines within the complex at 6.7~keV (1.9~\AA) emitted during flares. The line complex includes the He-like Fe (\fexxv) resonance line…

Solar and Stellar Astrophysics · Physics 2015-06-03 K. J. H. Phillips

The occurrence of X-class solar flares and their potential impact on the space weather often receive great attention than other flares. But predicting when and where an X-class flare will occur is still a challenge. With the…

Mercury mission MESSENGER's %(MErcury Surface, Space ENvironment, GEochemistry, and Ranging Solar Assembly for X-rays (SAX) observed almost 700 solar flares between May 28, 2007 and August 19, 2013, as cataloged by…

Solar and Stellar Astrophysics · Physics 2021-01-06 Erica Lastufka , Säm Krucker

A statistical analysis of the relationship between solar energetic particles (SEPs) and properties of solar flares and coronal mass ejections (CMEs) is presented. SEP events during solar cycle 23 are selected which are associated with solar…

Solar and Stellar Astrophysics · Physics 2014-12-18 M. Dierckxsens , K. Tziotziou , S. Dalla , I. Patsou , M. S. Marsh , N. B. Crosby , O. Malandraki , G. Tsiropoula

We investigate how the magnetic loop length of solar flares relates to the timing between their thermal and nonthermal emission signatures. Our study analyzes a sample of 96 C-, M-, and X-class flares observed between 2013 and 2015 with…

Solar and Stellar Astrophysics · Physics 2026-02-24 S. M. Perriyil , S. S. Sadangaya , C. G. Giménez de Castro , P. J. A. Simões

Solar flares commonly have a hot onset precursor event" (HOPE), detectable from soft X-ray observations. Detecting this requires subtraction of pre-flare fluxes from the non-flaring Sun prior to the event, fitting an isothermal emission…

Solar and Stellar Astrophysics · Physics 2024-07-08 Hugh S. Hudson

White-light flares (WLFs) are energetic activity in stellar atmosphere. However, the observed solar WLF is relatively rare compared to stellar WLFs or solar flares observed at other wavelengths, limiting our further understanding…

Solar and Stellar Astrophysics · Physics 2024-08-13 Yingjie Cai , Yijun Hou , Ting Li , Jifeng Liu

Post-flare arcades are well-known components of solar flare evolution, which have been observed for several decades. Coronal rain, cascades of catastrophically-cooled plasma, outline the loops and provide eye-catching evidence of the recent…

Solar and Stellar Astrophysics · Physics 2022-11-09 Emily I. Mason , Kara L. Kniezewski

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

Accurate and reliable solar flare predictions are essential to mitigate potential impacts on critical infrastructure. However, the current performance of solar flare forecasting is insufficient. In this study, we address the task of…

Computer Vision and Pattern Recognition · Computer Science 2025-09-15 Yusuke Takagi , Shunya Nagashima , Komei Sugiura

A deep learning network, Long-Short Term Memory (LSTM) network, is used in this work to predict whether the maximum flare class an active region (AR) will produce in the next 24 hours is class $\Gamma$. We considered $\Gamma$ are $\ge M$,…

Solar and Stellar Astrophysics · Physics 2020-05-27 Xiantong Wang , Yang Chen , Gabor Toth , Ward B. Manchester , Tamas I. Gombosi , Alfred O. Hero , Zhenbang Jiao , Hu Sun , Meng Jin , Yang Liu

Neutrinos generated during solar flares remain elusive. However, after $50$ years of discussion and search, the potential knowledge unleashed by their discovery keeps the search crucial. Neutrinos associated with solar flares provide…

Solar and Stellar Astrophysics · Physics 2020-10-12 K. Okamoto , Y. Nakano , S. Masuda , Y. Itow , M. Miyake , T. Terasawa , S. Ito , M. Nakahata

The newly revised sunspot number series allows for placing historical geoeffective storms in the context of several hundred years of solar activity. Using statistical analyses of the Geostationary Operational Environmental Satellites (GOES)…

Solar and Stellar Astrophysics · Physics 2016-06-01 Lisa M. Winter , Rick Pernak , K. S. Balasubramaniam

Coronal mass ejections (CMEs) are major drivers of stellar space weather and can strongly influence the habitability of exoplanets. However, compared to the frequent occurrence of white-light flares, confirmed stellar CMEs remain extremely…

Solar and Stellar Astrophysics · Physics 2025-12-18 Yu Shi , Hong-Peng Lu , Li-Yun Zhang , Tian-Hao Su , Chao Tan

The Neupert effect refers to the strong correlation between the soft X-ray (SXR) light curve and the time-integrated hard X-rays (HXR) or microwave flux, which is frequently observed in solar flares. In this article, we therefore utilized…

Solar and Stellar Astrophysics · Physics 2024-04-04 Dong Li , Hanyang Dong , Wei Chen , Yang Su , Yu Huang , Zongjun Ning