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We investigate quasi-periodic coronal pulsations during the decay phase of an X 3.2 class flare on 14 May 2013, using soft X-ray data from the RHESSI satellite. Periodogram analyses of soft X-ray light curves show that 53 s and 72 s periods…

Solar and Stellar Astrophysics · Physics 2016-01-20 Partha Chowdhury , A. K. Srivastava , B. N. Dwivedi , Robert Sych , Y. -J. Moon

The unusually narrow X-ray source imaged with RHESSI during an impulsive spike lasting for $\sim$10~s during the GOES C7.9 flare on 25 September 2011 (SOL2011-09-25T03:32) was only $\sim$2~ arcsec wide and $\sim$10~arcsec long. Comparison…

Solar and Stellar Astrophysics · Physics 2020-01-08 Brian R. Dennis , Anne K. Tolbert

Observations of solar flares with RHESSI have shown X-ray sources traveling along flaring loops, from the corona down to the chromosphere and back up. The 28 November 2002 C1.1 flare, first observed with RHESSI by Sui et al. 2006 and…

Solar and Stellar Astrophysics · Physics 2016-02-17 Jeffrey W. Reep , Stephen J. Bradshaw , Gordon D. Holman

Understanding the dynamics of the quiet solar corona is important for answering key questions including the coronal heating problem. Multiple studies have suggested small-scale magnetic reconnection events may play a crucial role. These…

Solar and Stellar Astrophysics · Physics 2023-06-07 Surajit Mondal , Bin Chen , Sijie Yu

Enhanced continuum brightness is observed in many flares (''white light flares''), yet it is still unclear which processes contribute to the emission. To understand the transport of energy needed to account for this emission, we must first…

Solar and Stellar Astrophysics · Physics 2016-01-27 Lucia Kleint , Petr Heinzel , Phil Judge , Säm Krucker

We studied an X1.6 solar flare produced by NOAA AR 12602 on 2014 October 22. The entirety of this event was covered by RHESSI, IRIS, and Hinode/EIS, allowing analysis of the chromospheric response to a nonthermal electron driver. We derived…

Solar and Stellar Astrophysics · Physics 2022-09-07 Sean G. Sellers , Ryan O. Milligan , R. T. James McAteer

Context: The Yohkoh/HXT observations of Long Duration Events (LDEs) showed that the HXR emission (14-23 keV) is present for tens of minutes after flare maximum. Hence, some heating process is expected to exist during that time. The better…

Solar and Stellar Astrophysics · Physics 2015-05-27 Sylwester Kolomanski , Tomasz Mrozek , Urszula Bak-Steslicka

Fine-scale braiding of coronal magnetic loops by continuous footpoint motions may power coronal heating via nanoflares, which are spontaneous fine-scale bursts of internal reconnection. An initial nanoflare may trigger an avalanche of…

Solar and Stellar Astrophysics · Physics 2015-06-23 Sanjiv K. Tiwari , Caroline E. Alexander , Amy R. Winebarger , Ronald L. Moore

We present observations of recurrent active region coronal jets and derive their thermal and non-thermal properties, by studying the physical properties of the plasma simultaneously at the base footpoint, and along the outflow of jets. The…

Solar and Stellar Astrophysics · Physics 2022-08-31 Alin R. Paraschiv , Alina C. Donea , Philip G. Judge

We report on radiative hydrodynamic simulations of moderate and strong solar flares. The flares were simulated by calculating the atmospheric response to a beam of non-thermal electrons injected at the apex of a one-dimensional closed…

Astrophysics · Physics 2009-11-13 J. C. Allred , S. L. Hawley , W. P. Abbett , M. Carlsson

Solar flare ribbons are features in the lower atmosphere that show enhanced emission intensity, particularly noticeable in H$\alpha$ and EUV images of the transition region and upper chromosphere. In this study, we provide observational…

The energy and spectral shape of radio bursts may help us understand the generation mechanism of solar eruptions, including solar flares, CMEs, eruptive filaments, and various scales of jets. The different kinds of flares may have different…

Solar and Stellar Astrophysics · Physics 2022-01-05 Chengming Tan , Karl-Ludwig Klein , Yihua Yan , Satoshi Masuda , Baolin Tan , Jing Huang , Guowu Yuan

Solar flares often display pulsating and oscillatory signatures in the emission, known as quasi-periodic pulsations (QPP). QPP are typically identified during the impulsive phase of flares, yet in some cases, their presence is detected late…

Solar and Stellar Astrophysics · Physics 2019-04-17 Laura A. Hayes , Peter T. Gallagher , Brian R. Dennis , Jack Ireland , Andrew Inglis , Diana E. Morosan

Decades of astrophysical observations have convincingly shown that soft X-ray (SXR; ~0.1--10 keV) emission provides unique diagnostics for the high temperature plasmas observed in solar flares and active regions. SXR observations critical…

Instrumentation and Methods for Astrophysics · Physics 2017-01-04 Amir Caspi , Albert Y. Shih , Harry P. Warren , Marek Stęślicki , Janusz Sylwester

In this paper, the energy budgets of two single-loop like flares observed in X- ray are analysed under the assumption that non-thermal electrons (NTEs) are the only source of plasma heating during all phases of both events. The flares were…

Solar and Stellar Astrophysics · Physics 2014-06-19 R. Falewicz

Solar flare X-ray spectra are typically dominated by thermal bremsstrahlung emission in the soft X-ray ($\lesssim$10 keV) energy range; for hard X-ray energies ($\gtrsim$30 keV), emission is typically non-thermal from beams of electrons.…

Solar and Stellar Astrophysics · Physics 2020-04-08 James M. McTiernan , Amir Caspi , Harry P. Warren

We aim to find similarities and differences between microflares at coronal bright points found in quiet regions and coronal holes, and to study their relationship with large scale flares. Coronal bright points in quiet regions and in…

Solar and Stellar Astrophysics · Physics 2011-04-05 S. Kamio , W. Curdt , L. Teriaca , D. E. Innes

In this study we present the analysis of six solar flare events that occurred in 2022, using new data from the third-generation Miniature X-Ray Solar Spectrometer (MinXSS), also known as the Dual-zone Aperture X-ray Solar Spectrometer…

Solar and Stellar Astrophysics · Physics 2024-03-12 Anant Telikicherla , Thomas N. Woods , Bennet D. Schwab

Coronal waves, significant solar phenomena, act as diagnostic tools for scientists studying solar atmosphere properties. Here, we present a novel observation detailing how a coronal wave event, associated with an X5.0 class flare,…

We have obtained high resolution X-ray spectra of the coronally active binary, II Pegasi (HD 224085), covering the wavelength range of 1.5-25 Angstroms. For the first half of our 44 ksec observation, the source was in a quiescent state with…

Astrophysics · Physics 2009-11-06 David P. Huenemoerder , Claude R. Canizares , Norbert S. Schulz
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