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Related papers: Large flares (M1 - X7) in solar cycle 24

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The time evolution of the spectral index and the non-thermal flux in 24 impulsive solar hard X-ray flares of GOES class M was studied in RHESSI observations. The high spectral resolution allows for a clean separation of thermal and…

Astrophysics · Physics 2007-05-23 Paolo C. Grigis , Arnold O. Benz

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

Sunspots or active regions (ARs) with a delta-magnetic configuration are known to be associated with strong eruptions such as flares and mass ejections. This article investigates the relationship between delta-ARs and flares over the course…

Solar and Stellar Astrophysics · Physics 2025-10-28 Rohan E. Louis

We use multiwavelength data from space and ground based instruments to study the solar flares and coronal mass ejections (CMEs) on January 23, 2012 that were responsible for one of the largest solar energetic particle (SEP) events of solar…

As the Lyman-alpha (Lya) line of neutral hydrogen is the brightest emission line in the solar spectrum, detecting increases in irradiance due to solar flares at this wavelength can be challenging due to the very high background. Previous…

Solar and Stellar Astrophysics · Physics 2021-03-31 Ryan O. Milligan

Until now, how the magnetic fields in M/X-class flaring active regions (ARs) differ from C-class flaring ARs remains unclear. Here, we calculate the key magnetic field parameters within the area of high photospheric free energy density (HED…

Solar and Stellar Astrophysics · Physics 2024-03-01 Ting Li , Yanfang Zheng , Xuefeng Li , Yijun Hou , Xuebao Li , Yining Zhang , Anqin Chen

The solar active region NOAA 11158 produced a series of flares during its passage through the solar disk. The first major flare (of class X2.2) of the current solar cycle occurred in this active region on 2011 February 15 around 01:50 UT.…

Solar and Stellar Astrophysics · Physics 2015-06-17 A. Raja Bayanna , Brajesh Kumar , P. Venkatakrishnan , Shibu K Mathew , B. Ravindra , Savita Mathur , R. A. Garcia

We investigate the flare-frequency distributions of 5 M-dwarfs that experienced superflares with energies in excess of $10^{33}$ erg detected by ASAS-SN. We use K2 and TESS short-cadence observations along with archival ASAS-SN data to…

In this paper, solar cycles 21 to 24 were compared using complex network analysis. A network was constructed for these four solar cycles to facilitate the comparison. In these networks, the nodes represent the active regions of the Sun that…

Solar and Stellar Astrophysics · Physics 2024-12-17 Eduardo Flández , Alejandro Zamorano , Víctor Muñoz

This paper is an attempt to understand the physical processes occurring in different layers of solar atmosphere during a solar flare. For a complete understanding of the flare we must analyze multi-wavelength datasets, as emission at…

Solar and Stellar Astrophysics · Physics 2020-09-30 Shirsh Lata Soni , Radhe Shyam Gupta , Adya Prasad Mishra

The current fleet of space-based solar observatories offers us a wealth of opportunities to study solar flares over a range of wavelengths. Significant advances in our understanding of flare physics often come from coordinated observations…

Solar and Stellar Astrophysics · Physics 2018-02-14 Ryan O. Milligan , Jack Ireland

We study the energy release process of a set of 51 flares (32 confined, 19 eruptive) ranging from GOES class B3 to X17. We use H$\alpha$ filtergrams from Kanzelh\"ohe Observatory together with SDO HMI and SOHO MDI magnetograms to derive…

Solar and Stellar Astrophysics · Physics 2018-02-07 Johannes Tschernitz , Astrid M. Veronig , Julia K. Thalmann , Jürgen Hinterreiter , Werner Pötzi

Solar flares sometimes lead to coronal mass ejections that directly affect the Earth's environment. However, a large fraction of flares, including on solar-type stars, are confined flares. What are the differences in physical properties…

Solar and Stellar Astrophysics · Physics 2023-10-18 Maria D. Kazachenko

Solar flares and coronal mass ejections (CMEs) are among the most energetic phenomena in the solar system, often impacting space weather and terrestrial technologies. In this study, we utilize SunPy, an open-source Python library for solar…

Solar and Stellar Astrophysics · Physics 2026-01-12 Akash Vinod Shirke , Sakshi Sheshrao Charde , Balendra Pratap Singh

We studied the soft X-ray data of solar flares and found that the distribution functions of flare fluence are successfully modeled by tapered power law or gamma function distributions whose power exponent is slightly smaller than 2,…

Solar and Stellar Astrophysics · Physics 2022-12-07 Takashi Sakurai

We present the result of comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we…

Solar and Stellar Astrophysics · Physics 2017-08-30 A. S. Kirichenko , S. A. Bogachev

In this paper, we have made a statistical analysis of solar H$\alpha$ flares that occurred during the period 1996 to 2005 to investigate their spatial distribution with respect to northern and southern hemispheres of the Sun. The analysis…

Astrophysics · Physics 2007-08-16 Bhuwan Joshi , P. Pant , P. K. Manoharan , Kavita Pandey

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

The correlation coefficients of the linear regression of six solar indices versus F10,7 were analyzed in solar cycles 21, 22 and 23. We also analyzed the interconnection between these indices and F10,7 with help of the approximation by the…

Solar and Stellar Astrophysics · Physics 2015-10-06 E. A. Bruevich , V. V. Bruevich

During late October 2014, active region NOAA 2192 caused an unusual high level of solar activity, within an otherwise weak solar cycle. While crossing the solar disk, during a period of 11 days, it was the source of 114 flares of GOES class…

Solar and Stellar Astrophysics · Physics 2017-01-11 Julia K. Thalmann , Yang Su , Manuela Temmer , Astrid M. Veronig