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Solar flares are one of the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of…

Solar and Stellar Astrophysics · Physics 2017-02-08 Y. Li , X. Sun , M. D. Ding , J. Qiu , E. R. Priest

Prediction of solar flares is an important task in solar physics. The occurrence of solar flares is highly dependent on the structure and the topology of solar magnetic fields. A new method for predicting large (M and X class) flares is…

Solar and Stellar Astrophysics · Physics 2016-12-28 Abbas Raboonik , Hossein Safari , Nasibe Alipour , Michael S. Wheatland

NASA's Solar Dynamics Observatory (SDO) Extreme-ultraviolet Variability Experiment (EVE) has been making solar full-disk extreme ultraviolet (EUV) spectral measurements since 2010 over the spectral range of 6nm to 106nm with 0.1nm spectral…

We present the results of a campaign to observe flares on the M dwarf flare star EV Lacertae over the course of two days in 2001 September, utilizing a combination of radio continuum, optical photometric and spectroscopic, ultraviolet…

Astrophysics · Physics 2009-11-10 R. A. Osten , S. L. Hawley , J. C. Allred , C. M. Johns-Krull , C. Roark

We estimated photospheric velocities by separately applying the Fourier Local Correlation Tracking (FLCT) and Differential Affine Velocity Estimator (DAVE) methods to 2708 co-registered pairs of SOHO/MDI magnetograms, with nominal 96-minute…

Solar and Stellar Astrophysics · Physics 2009-11-13 B. T. Welsch , Y. Li , P. W. Schuck , G. H. Fisher

One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often…

Solar and Stellar Astrophysics · Physics 2015-06-12 Harry P. Warren , John T. Mariska , George A. Doschek

Stellar flares are characterized by sudden enhancement of electromagnetic radiation from the atmospheres of stars. Compared to their solar counterparts, our knowledge on the coronal plasma dynamics of stellar flares and their connection to…

Solar and Stellar Astrophysics · Physics 2022-07-20 Hechao Chen , Hui Tian , Hao Li , Jianguo Wang , Hongpeng Lu , Yu Xu , Zhenyong Hou , Yuchuan Wu

This thesis strives to improve our understanding of solar activity, specifically the behaviour of solar flares and coronal mass ejections. An investigation into the hydrodynamic evolution of a confined solar flare was carried out using…

Solar and Stellar Astrophysics · Physics 2012-10-19 Claire L. Raftery

We describe the optical spectropolarimetric monitoring program at Steward Observatory centered around gamma-ray-bright blazars and the LAT Monitored Source List planned for Fermi Cycles 2-4. The large number of measurements made during…

High Energy Astrophysical Phenomena · Physics 2009-12-21 P. S. Smith , E. Montiel , S. Rightley , J. Turner , G. D. Schmidt , B. T. Jannuzi

The Extreme ultraviolet Variability Experiment was designed to observe the Sun-as-a-star in the extreme ultraviolet; a wavelength range that has remained spectrally unresolved for many years. It has provided a wealth of data on solar…

Solar and Stellar Astrophysics · Physics 2018-12-26 Marcos E. Machado , Ryan O. Milligan , Paulo J. A. Simoes

We used multi-wavelength high-resolution data from ARIES, THEMIS, and SDO instruments, to analyze a non-standard, C3.3 class flare produced within the active region NOAA 11589 on 2012 October 16. Magnetic flux emergence and cancellation…

Solar and Stellar Astrophysics · Physics 2016-02-22 K. Dalmasse , R. Chandra , B. Schmieder , G. Aulanier

We present a detailed investigation on the evolution of observed net vertical current using a time series of vector magnetograms of the active region (AR) NOAA 11158 obtained from Helioseismic Magnetic Imager. We also discuss the relation…

Solar and Stellar Astrophysics · Physics 2015-09-16 P. Vemareddy , P. Venkatakrishnan , S. Karthikreddy

During the rising phase of Solar Cycle 24 tremendous activity occurred on the Sun with fast and compact emergence of magnetic flux leading to bursts of flares (C to M and even X-class). We investigate the violent events occurring in the…

Solar and Stellar Astrophysics · Physics 2015-06-18 C. H. Mandrini , B. Schmieder , P. Démoulin , Y. Guo , G. D. Cristiani

Context: The origin of the variable component of the solar wind is of great intrinsic interest for heliophysics and space-weather, e.g. the initiation of coronal mass ejections, and the problem of mass loss of all stars. It is also related…

Solar and Stellar Astrophysics · Physics 2015-05-28 K. Bocchialini , F. Baudin , S. Koutchmy , G. Pouget , J. Solomon

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

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

Context: Solar active regions (ARs) are key manifestations of the Sun's magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and…

Solar and Stellar Astrophysics · Physics 2025-08-06 M. Švanda , J. Jurčák , M. Schmassmann

Using the multi-wavelength data from Atmospheric Imaging Assembly on board the Solar Dynamic Observatory, we investigated two successive solar flares, a C5.1 confined flare and an X4.9 ejective flare with a halo coronal mass ejection,in…

Solar and Stellar Astrophysics · Physics 2015-06-23 Huadong Chen , Jun Zhang , Xin Cheng , Suli Ma , Shuhong Yang , Ting Li

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