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The large (X-ray class > M1) and very large (X-ray class >X1) flares (according to the observations of GOES-15 and Preliminary data from Current Catalog of Flare Events) in solar activity cycle 24 were analyzed. The monthly average values…

Solar and Stellar Astrophysics · Physics 2018-03-21 E. A. Bruevich , T. V. Kazachevskaya , G. V. Yakunina

Solar flares stronger than X10 (S-flares, >X10) are the highest class flares which significantly impact on the Sun's evolution and space weather. Based on observations of Geostationary Orbiting Environmental Satellites (GOES) at soft X-ray…

Solar and Stellar Astrophysics · Physics 2025-01-10 Baolin Tan , Yin Zhang , Jing Huang , Kaifan Ji

We present a clear case study on the occurrence of two successive X-class flares including a decade-class flare (X9.3) and two coronal mass ejections (CMEs) triggered by shearing motion and sunspot rotation in active region NOAA 12673 on…

Solar and Stellar Astrophysics · Physics 2018-04-11 X. L. Yan , J. C. Wang , G. M. Pan , D. F. Kong , Z. K. Xue , L. H. Yang , Q. L. Li , X. S. Feng

In a recent work, Kilcik et al. (2017), have detected the temporal and periodic behavior of sunspot counts (SSC) in flaring (i.e. C, M, or X class flares), and non-flaring active regions for the last two solar cycles, covering the period:…

Solar and Stellar Astrophysics · Physics 2017-07-10 Stefano Sello

In an effort to examine the relationship between flare flux and corresponding CME mass, we temporally and spatially correlate all X-ray flares and CMEs in the LASCO and GOES archives from 1996 to 2006. We cross-reference 6,733 CMEs having…

Solar and Stellar Astrophysics · Physics 2015-05-20 Alicia N. Aarnio , Keivan G. Stassun , W. Jeffrey Hughes , Sarah L. McGregor

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

We have analyzed the intermediate term periodicities in soft X-ray flare index ($FI_{SXR}$) during solar cycles 21, 22 and 23. Power spectral analysis of daily $FI_{SXR}$ reveals a significant period of 161 days in cycle 21 which is absent…

Astrophysics · Physics 2007-05-23 Bhuwan Joshi , Anita Joshi

Temporal and spectral characteristics of X-ray emission from 60 flares of intensity $\ge$C class observed by Solar X-ray Spectrometer (SOXS) during 2003-2011 are presented. We analyse the X-ray emission observed in four and three energy…

Solar and Stellar Astrophysics · Physics 2018-10-17 Veena Choithani , Rajmal Jain , Arun Kumar Awasthi , Geetanjali Singh , Sneha Chaudhari , Som Kumar Sharma

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

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

We present a statistical analysis of properties of Soft X-Ray (SXR) emission, plasma temperature (T), and emission measure (EM), derived from GOES observations of flares in 2002-2017. The temperature and emission measures are obtained using…

Solar and Stellar Astrophysics · Physics 2019-03-27 Viacheslav M Sadykov , Alexander G Kosovichev , Irina N Kitiashvili , Alexander Frolov

In this paper the N-S asymmetry of the soft X-ray flare index during the solar cycles 21, 22 and 23 has been analyzed. The results show the existence of a real N-S asymmetry which is strengthened during solar minimum. The slope of the…

Astrophysics · Physics 2008-11-26 Bhuwan Joshi , Anita Joshi

The paper presents results of a search for helioseismic events (sunquakes) produced by M-X class solar flares during Solar Cycle 24. The search is performed by analyzing photospheric Dopplergrams from Helioseismic Magnetic Imager (HMI).…

Solar and Stellar Astrophysics · Physics 2020-06-03 I. N. Sharykin , A. G. Kosovichev

The timing of 503 solar flares observed simultaneously in hard X-rays, soft X-rays and H-alpha is analyzed. We investigated the start and the peak time differences in different wavelengths, as well as the differences between the end of the…

Astrophysics · Physics 2015-06-24 A. Veronig , B. Vrsnak , M. Temmer , A. Hanslmeier

The relationships between solar flare parameters (total importance, time duration, flare index, and flux) and sunspot activity (Rz) as well as those between geomagnetic activity (aa index) and the flare parameters can be well described by…

Solar and Stellar Astrophysics · Physics 2015-06-03 Z. L. Du , H. N. Wang

We have statistically analyzed 379 radio-loud (RL) CMEs and their associated flares during the period 1996 - 2019 covering both solar cycles (SC) 23 and 24. We classified them into two sets of populations based on the observation period: i)…

Solar and Stellar Astrophysics · Physics 2022-05-25 P. Pappa Kalaivani , O. Prakash , A. Shanmugaraju , G. Michalek , G. Selvarani

The soft X-ray emissions of solar flares come mainly from the bright coronal loops at the highest temperatures normally achieved in the flare process. Their ubiquity has led to their use as a standard measure of flare occurrence and energy,…

Solar and Stellar Astrophysics · Physics 2015-06-03 Paulo J. A. Simões , Hugh S. Hudson , Lyndsay Fletcher

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 statistically study the relationship between the Lyman-alpha (\lya) and 1--8 \AA\ soft X-ray (SXR) emissions from 658 M- and X-class solar flares observed by the {\em Geostationary Operational Environmental Satellite} during 2006--2016.…

Solar and Stellar Astrophysics · Physics 2020-11-25 Zhichen Jing , Wuqi Pan , Yukun Yang , Dechao Song , Jun Tian , Y. Li , X. Cheng , Jie Hong , M. D. Ding

The statistical characteristic of stellar flares at optical bands has received an extensive study, but it remains to be studied at soft X-ray bands, in particular for solar-type stars. Here, we present a statistical study of soft X-ray…

Solar and Stellar Astrophysics · Physics 2024-01-19 Zhanhao Zhao , Ziqian Hua , Xin Cheng , Zhiyuan Li , Mingde Ding