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Related papers: Decay Phase Cooling and Inferred Heating of M- and…

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All three components of the current density are required to compute the heating rate due to free magnetic energy dissipation. Here we present a first test of a new model developed to determine if the times of increases in the resistive…

Solar and Stellar Astrophysics · Physics 2020-04-29 Michael L. Goodman , Chiman Kwan , Bulent Ayhan , Eric L. Shang

This paper presents measurements of the energy radiated by the lower solar atmosphere, at optical, UV, and EUV wavelengths, during an X-class solar flare (SOL2011-02-15T01:56) in response to an injection of energy assumed to be in the form…

Solar flare activity in cycle 24 is studied. Satellite observations of x-ray fluxes from GOES-15 and UV emission lines from the SDO/EVE experiment are used. The most powerful flares of cycle 24 in classes X9.3 and X8.2 in September 2017 are…

Solar and Stellar Astrophysics · Physics 2018-07-04 E. A. Bruevich , V. V. Bruevich

A primary characteristic of solar flares is the efficient acceleration of electrons to nonthermal deka-keV energies. While hard X-Ray (HXR) observation of bremsstrahlung emission serves as the key diagnostic of these electrons. In this…

Solar and Stellar Astrophysics · Physics 2025-06-11 Debesh Bhattacharjee , Eduard P. Kontar , Yingjie Luo

The collisional thick target model, wherein a large number of electrons are accelerated down a flaring loop, can be used to explain many observed properties of solar flares. In this study, we focus on the sensitivity of GOES flare…

Solar and Stellar Astrophysics · Physics 2015-06-29 Jeffrey Reep , Stephen Bradshaw , R. T. James McAteer

Numerical simulations with varying realism indicate an emergent principle -- multiphase condensation and large cavity power occur when the ratio of the cooling time to the free-fall time ($t_{\rm cool}/t_{\rm ff}$) falls below a threshold…

Astrophysics of Galaxies · Physics 2022-08-22 Kartick C Sarkar , Arjun Dey , Prateek Sharma

The origin of the near-ultraviolet and optical continuum radiation in flares is critical for understanding particle acceleration and impulsive heating in stellar atmospheres. Radiative-hydrodynamic simulations in 1D have shown that high…

Solar and Stellar Astrophysics · Physics 2018-01-10 Adam F. Kowalski , Joel C. Allred

The energy released in a solar flare is partitioned between thermal and non-thermal particle energy and lost to thermal conduction and radiation over a broad range of wavelengths. It is difficult to determine the conductive losses and the…

Astrophysics · Physics 2011-02-11 J. C. Raymond , G. Holman , A. Ciaravella , A. Panasyuk , Y. -K. Ko , J. Kohl

The energy input into the lower solar corona by flare evaporation events has been modeled according to the available observations for quiet regions. The question is addressed whether such heating events can provide the observed average…

Astrophysics · Physics 2008-11-26 U. Mitra-Kraev , A. O. Benz

Spectroscopic observations in X-ray wavelengths provide excellent diagnostics of the temperature distribution in solar flare plasma. The Solar X-ray Monitor (XSM) onboard the Chandrayaan-2 mission provides broad-band disk integrated soft…

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

A new estimation of the total number and energy of the non-thermal electrons produced in the giant ($>\text{X}17$) solar flare on 2003 October 28 is presented based on the analysis of the observations of the hard X-ray (HXR) emission by the…

Solar and Stellar Astrophysics · Physics 2018-09-05 B. A. Nizamov , I. V. Zimovets , D. V. Golovin , A. B. Sanin , M. L. Litvak , V. I. Tretyakov , I. G. Mitrofanov , A. S. Kozyrev

Large solar flares (GOES M-class or higher) are usually associated with eruptions of material. However, when considering flare irradiance enhancements and dynamics such as chromospheric evaporation, potential contributions from erupted…

Solar and Stellar Astrophysics · Physics 2025-12-18 Luke Majury , Marie Dominique , Ryan Milligan , Dana-Camelia Talpeanu , Ingolf Dammasch , David Berghmans

This study entails the third part of a global flare energetics project, in which Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) data of 191 M and X-class flare events from the first 3.5 yrs of the Solar Dynamics Observatory (SDO)…

Solar and Stellar Astrophysics · Physics 2018-03-28 Markus J. Aschwanden , Gordon Holman , Aidan O'Flannagain , Amir Caspi , James M. McTiernan , Eduard Kontar

The impulsive phase of solar flares is a time of rapid energy deposition and heating in the lower solar atmosphere, leading to changes in the temperature and density structure of the region. We use an O V density diagnostic formed of the…

Solar and Stellar Astrophysics · Physics 2015-11-18 David R. Graham , Lyndsay Fletcher , Nicolas Labrosse

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

Temporally-resolved electron density measurements of solar flare plasmas are presented using data from the EUV Variability Experiment (EVE) onboard the Solar Dynamics Observatory (SDO). The EVE spectral range contains emission lines formed…

Solar and Stellar Astrophysics · Physics 2015-06-05 Ryan O. Milligan , Michael B. Kennedy , Mihalis Mathioudakis , Francis P. Keenan

Solar flares are 3D phenomenon but modelling a flare in 3D, including many of the important processes in the chromosphere, is a computational challenge. Accurately modelling the chromosphere is important, even if the transition region and…

Solar and Stellar Astrophysics · Physics 2020-09-02 Graham S. Kerr , Joel C. Allred , Vanessa Polito

Solar flare activity is characterised by different classification systems, both in optical and X-ray ranges. The most generally accepted classifications of solar flares describe important parameters of flares such as the maximum of…

Solar and Stellar Astrophysics · Physics 2022-12-28 Elena Bruevich