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Solar flare X-ray emission results from rapidly increasing temperatures and emission measures in flaring active region loops. To date, observations from the X-Ray Sensor (XRS) onboard the Geostationary Operational Environmental Satellite…

Solar and Stellar Astrophysics · Physics 2013-03-07 Daniel F. Ryan , Ryan O. Milligan , Peter T. Gallagher , Brian R. Dennis , A. Kim Tolbert , Richard A. Schwartz , C. Alex Young

Understanding how energy is released in flares is one of the central problems of solar and stellar astrophysics. Observations of high temperature flare plasma hold many potential clues as to the nature of this energy release. It is clear,…

Solar and Stellar Astrophysics · Physics 2020-05-27 Jeffrey W. Reep , Harry P. Warren , Christopher S. Moore , Crisel Suarez , Laura A. Hayes

In previous works we have developed a method to convert solar X-ray data, collected with the Yohkoh/SXT, into templates of stellar coronal observations. Here we apply the method to several solar flares, for comparison with stellar X-ray…

Astrophysics · Physics 2009-11-06 F. Reale , G. Peres , S. Orlando

Observations of extreme-ultraviolet (EUV) emission from an X-class solar flare that occurred on 2011 February 15 at 01:44 UT are presented, obtained using the EUV Variability Experiment (EVE) onboard the Solar Dynamics Observatory. The…

Spectral lines allow us to probe the thermodynamics of the solar atmosphere, but the shape of a single spectral line may be similar for different thermodynamic solutions. Multiline analyses are therefore crucial, but computationally…

Solar and Stellar Astrophysics · Physics 2021-05-19 Brandon Panos , Lucia Kleint , Sviatoslav Voloshynovskiy

Solar flares are observed and classified according to their intensity measured with the GOES X-ray Sensors. We show that the duration of a flare, as measured by the full width at half maximum (FWHM) in GOES is not related to the size of the…

Solar and Stellar Astrophysics · Physics 2019-04-10 Jeffrey W. Reep , Kalman J. Knizhnik

The light curves of solar flares in the impulsive phase are complex in general, indicating that multiple physical processes are involved in. With the GOES (Geostationary Operational Environmental Satellite) observations, we find that there…

Solar and Stellar Astrophysics · Physics 2015-06-16 HAN , Fei-ran , LIU , Si-ming

We extend a previous statistical solar flare study of 155 GOES M- and X-class flares observed with AIA/SDO (Aschwanden 2012) to all 7 coronal wavelengths (94, 131, 171, 193, 211, 304, 335 \ang) to test the wavelength-dependence of scaling…

Solar and Stellar Astrophysics · Physics 2015-06-17 Markus J. Aschwanden , Jie Zhang , Kai Liu

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

Spatially-resolved X-ray observations are the key to understanding electron acceleration in solar flares. Currently, the underlying processes that efficiently energize solar flare particles are poorly constrained. Abundant flare…

Solar and Stellar Astrophysics · Physics 2026-03-09 Morgan Stores , Natasha Jeffrey , Ewan Dickson , James McLaughlin , Eduard Kontar

Spectroscopic observations of solar flares provide critical diagnostics of the physical conditions in the flaring atmosphere. Some key features in observed spectra have not yet been accounted for in existing flare models. Here we report a…

Solar and Stellar Astrophysics · Physics 2016-08-16 Fatima Rubio da Costa , Lucia Kleint , Vahé Petrosian , Wei Liu , Joel C. Allred

The GOES X1 flare SOL2014-10-25T17:08:00 was a three-ribbon solar flare observed with IRIS in the near and far ultraviolet. One of the flare ribbons crossed a sunspot umbra, producing a dramatic, $\sim1000$% increase in the near-ultraviolet…

Introducing thresholds to analyze time series of emission from the Sun enables a new and simple definition of solar flare events, and their interoccurrence times. Rescaling time by the rate of events, the waiting and quiet time…

Statistical Mechanics · Physics 2007-05-23 Marco Baiesi , Maya Paczuski , Attilio L. Stella

The solar X-ray irradiance is significantly heightened during the course of a solar flare, which can cause radio blackouts due to ionization of the atoms in the ionosphere. As the duration of a solar flare is not related to the size of that…

Solar and Stellar Astrophysics · Physics 2021-11-10 Jeffrey W. Reep , Will T. Barnes

In this paper, the cooling of 72 M- and X-class flares is examined using GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the observed total cooling times are compared to the predictions of an analytical 0-D hydrodynamic…

Solar and Stellar Astrophysics · Physics 2014-01-17 Daniel F. Ryan , Phillip C. Chamberlin , Ryan O. Milligan , Peter T. Gallgher

The Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory obtains extreme-ultraviolet (EUV) spectra of the full-disk Sun at a spectral resolution of ~1 A and cadence of 10 s. Such a spectral resolution would…

Solar and Stellar Astrophysics · Physics 2017-04-12 F. P. Keenan , R. O. Milligan , M. Mathioudakis , D. J. Christian

Extreme ultraviolet (EUV) solar flare emissions evolve in time as the emitting plasma heats and then cools. Although accurately modeling this evolution has been historically difficult, especially for empirical relationships, it is important…

Solar and Stellar Astrophysics · Physics 2017-11-28 Edward M. B. Thiemann , Francis G. Eparvier , Thomas N. Woods

Deriving a well-constrained differential emission measure (DEM) distribution for solar flares has historically been difficult, primarily because no single instrument is sensitive to the full range of coronal temperatures observed in flares,…

Solar and Stellar Astrophysics · Physics 2014-06-25 Amir Caspi , James M. McTiernan , Harry P. Warren

In this study we compile for the first time comprehensive data sets of solar and stellar flare parameters, including flare peak temperatures T_p, flare peak volume emission measures EM_p, and flare durations t_f from both solar and stellar…

Astrophysics · Physics 2009-11-13 Markus J. Aschwanden , Robert A. Stern , Manuel Güdel

Analysis of spectra obtained with the gamma-ray spectrometer SPI onboard INTEGRAL of the GOES X17-class flare on October 28, 2003 is presented. In the energy range 600 keV - 8 MeV three prominent narrow lines at 2.223, 4.4 and 6.1 MeV,…

Astrophysics · Physics 2009-11-11 J. Kiener , M. Gros , V. Tatischeff , G. Weidenspointner