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Related papers: Flare Impulsive-phase Durations

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Context. Hard X-ray (HXR) spikes refer to fine time structures on timescales of seconds to milliseconds in high-energy HXR emission profiles during solar flare eruptions. Aims. We present a preliminary statistical investigation of temporal…

Solar and Stellar Astrophysics · Physics 2015-06-11 J. X. Cheng , J. Qiu , M. D. Ding , H. Wang

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

We investigate the relationship between the continuum enhancement and the hard X-ray (HXR) emission of a white-light flare on 2002 September 29. By reconstructing the RHESSI HXR images in the impulsive phase, we find two bright conjugate…

Astrophysics · Physics 2014-10-13 Q. R. Chen , M. D. Ding

The Neupert effect refers to the strong correlation between the soft X-ray (SXR) light curve and the time-integrated hard X-rays (HXR) or microwave flux, which is frequently observed in solar flares. In this article, we therefore utilized…

Solar and Stellar Astrophysics · Physics 2024-04-04 Dong Li , Hanyang Dong , Wei Chen , Yang Su , Yu Huang , Zongjun Ning

In this paper we analyze soft and hard X-ray emission of the 2002 September 20 M1.8 GOES class solar flare observed by RHESSI and GOES satellites. In this flare event, soft X-ray emission precedes the onset of the main bulk hard X-ray…

Solar and Stellar Astrophysics · Physics 2014-11-20 M. Siarkowski , R. Falewicz , P. Rudawy

[Abridged]We present analysis of a pair of unusually energetic coronal hard X-ray (HXR) sources detected by RHESSI during the impulsive phase of an X3.9 class solar flare on 2003 November 3, which simultaneously shows two intense footpoint…

Solar and Stellar Astrophysics · Physics 2015-06-03 Qingrong Chen , Vahe Petrosian

The aim of the present paper is to use quasi-periodic oscillations in hard X-rays (HXRs) of solar flares as a diagnostic tool for investigation of impulsive electron acceleration. We have selected a number of flares which showed…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. Jakimiec , M. Tomczak

In our recent paper (Solar Physics 261, 233) we investigated quasi-periodic oscillations of hard X-rays during impulsive phase of solar flares. We have come to conclusion that they are caused by magnetosonic oscillations of magnetic traps…

Solar and Stellar Astrophysics · Physics 2015-06-17 J. Jakimiec , M. Tomczak

X-ray and EUV observations are an important diagnostic of various plasma parameters of the solar atmosphere during solar flares. Soft X-ray and EUV observations often show coronal sources near the top of flaring loops, while hard X-ray…

Solar and Stellar Astrophysics · Physics 2015-06-11 Marina Battaglia , Eduard P. Kontar

Solar flares are known to be prolific electron accelerators, yet identifying the mechanism(s) for such efficient electron acceleration in solar flare (and similar astrophysical settings) presents a major challenge. This is due in part to a…

Solar and Stellar Astrophysics · Physics 2023-04-18 Eduard P. Kontar , A. Gordon Emslie , Galina G. Motorina , Brian R. Dennis

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

Recent progress in the diagnosis of flare fast particles is critically discussed with the main emphasis on high resolution Hard X-Ray (HXR) data from RHESSI and coordinated data from other instruments. Spectacular new photon data findings…

Astrophysics · Physics 2009-11-11 John C. Brown , Eduard P. Kontar

We present systematic analysis of spatio-temporal evolution of sources of hard X-ray (HXR) pulsations in solar flares. We concentrate on disk flares whose impulsive phase are accompanied by a series of more than three peaks (pulsations) of…

Solar and Stellar Astrophysics · Physics 2016-08-25 S. A. Kuznetsov , I. V. Zimovets , A. S. Morgachev , A. B. Struminsky

We investigate the solar flare of 20 October 2002. The flare was accompanied by quasi-periodic pulsations (QPP) of both thermal and nonthermal hard X-ray emissions (HXR) observed by RHESSI in the 3-50 keV energy range. Analysis of the HXR…

Solar and Stellar Astrophysics · Physics 2015-05-14 I. V. Zimovets , A. B. Struminsky

We study the correlation between abrupt permanent changes of magnetic field during X-class flares observed by the GONG and HMI instruments, and the hard X-ray (HXR) emission observed by RHESSI, to relate the photospheric field changes to…

Solar and Stellar Astrophysics · Physics 2015-05-05 O. Burtseva , J. C. Martínez-Oliveros , G. J. D. Petrie , A. A. Pevtsov

We investigate the August 9, 2011 solar flare of X-ray class X6.9, the "hottest" flare from 2000 to 2012, with a peak plasma temperature according to GOES data of 32.5 MK. Our goal is to determine the cause of such an anomalously high…

Solar and Stellar Astrophysics · Physics 2015-06-23 I. N. Sharykin , A. B. Struminsky , I. V. Zimovets

We carried out detailed analysis of X-ray and radio observations of a simple flare loop that occurred on 12th August 2002, with the impulsive hard X-ray (HXR) light curves dominated by a single pulse. The emission spectra of the early…

Solar and Stellar Astrophysics · Physics 2015-06-22 I. N. Sharykin , S. Liu , L. Fletcher

We propose that non-thermal electrons are efficiently accelerated by first-order Fermi process at the fast shock, as a natural consequence of the new magnetohydrodynamic picture of the flaring region revealed with Yohkoh. An oblique fast…

Astrophysics · Physics 2009-10-30 Saku Tsuneta , Tsuguya Naito

We use RHESSI high-resolution imaging and spectroscopy observations from ~6 to 100 keV to determine the statistical relationships between measured parameters (temperature, emission measure, etc.) of hot, thermal plasma in 37 intense (GOES…

Solar and Stellar Astrophysics · Physics 2014-06-25 Amir Caspi , Säm Krucker , R. P. Lin

We present a multi-wavelength analysis of two flare-related jets on November 13, 2014, using data from SDO/AIA, RHESSI, Hinode/XRT, and IRIS. Unlike most coronal jets where hard X-ray (HXR) emissions are usually observed near the jet base,…

Solar and Stellar Astrophysics · Physics 2022-07-13 Yixian Zhang , Sophie Musset , Lindsay Glesener , Navdeep Panesar , Gregory Fleishman