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Related papers: YOHKOH remnants: partially occulted flares in hard…

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Flares close to the solar limb, where the footpoints are occulted, can reveal the spectrum and structure of the coronal loop-top source in X-rays. We aim at studying the properties of the corresponding energetic electrons near their…

The discovery of hard X-ray sources near the top of a flaring loop by the HXT instrument on board the YOHKOH satellite represents a significant progress towards the understanding of the basic processes driving solar flares. In this paper we…

Astrophysics · Physics 2009-11-07 Vahe' Petrosian , Timothy Q. Donaghy , James M. McTiernan

At hard X-ray energies, the bright footpoint emission from solar flare loops often prevents a detailed analysis of the weaker loop-top source morphology due to the limited dynamic range available for X-ray imaging. Here, we study the X1.3…

Solar and Stellar Astrophysics · Physics 2016-12-21 Frederic Effenberger , Fatima Rubio da Costa , Vahe Petrosian

The discovery of hard X-rays from tops of flaring loops by the HXT of YOHKOH represents a significant progress in the understanding of solar flares. This report describes the properties of 20 limb flares observed by YOHKOH from October 1991…

Astrophysics · Physics 2007-05-23 Vahé Petrosian

We report the first science results from the newly completed Expanded Owens Valley Solar Array (EOVSA), which obtained excellent microwave imaging spectroscopy observations of SOL2017-09-10, a classic partially-occulted solar limb flare…

The hard X-ray flux ratio R of the footpoint sources to the loop-top source has been used to investigate non-thermal electron trapping and precipitation in solar flares. Considering the mission-long Yohkoh Hard X-ray Telescope database,…

Astrophysics · Physics 2009-11-11 M. Tomczak , T. Ciborski

Context: Hard X-ray emission of coronal sources in solar flares has been observed and studied since its discovery in Yohkoh observations. Several models have been proposed to explain the physical mechanisms causing this emission and the…

Astrophysics · Physics 2009-11-13 Marina Battaglia , Arnold O. Benz

Solar hard X-rays (HXRs) appear in the form of either footpoint sources or coronal sources, and each individual source provides its own critical information on acceleration of nonthermal electrons and plasma heating. Earlier studies found…

Solar and Stellar Astrophysics · Physics 2019-06-11 Hao Ning , Yao Chen , Jeongwoo Lee , Zhao Wu , Yang Su , Xiang-Liang Kong

Understanding the relationship among different emission components plays an essential role in the study of particle acceleration and energy conversion in solar flares. In flares where gradual and impulsive emission components can be readily…

Solar and Stellar Astrophysics · Physics 2015-06-15 Siming Liu , Youping Li , Lyndsay Fletcher

We conduct a detailed analysis of an M1.3 limb flare occurring on 2017 July 3, which have the X-ray observations recorded by multiple hard X-ray telescopes, including Hard X-ray Modulation Telescope (Insight-HXMT), Ramaty High Energy Solar…

High Energy Astrophysical Phenomena · Physics 2022-05-04 Ping Zhang , Wei Wang , Yang Su , Shuangnan Zhang , Liming Song , Fangjun Lu , Shu Zhang

Gamma-ray emitting solar flares observed with Yohkoh were analyzed from a statistical viewpoint. The four-band hard X-ray (15--95 keV) photometric data, taken with the Hard X-ray Telescope onboard Yohkoh, were utilized in combination with…

We present a concept for a machine-learning classification of hard X-ray (HXR) emissions from solar flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), identifying flares that are either occulted by the…

Solar and Stellar Astrophysics · Physics 2021-02-24 Shin-nosuke Ishikawa , Hideaki Matsumura , Yasunobu Uchiyama , Lindsay Glesener

Context: Solar flares release a large fraction of their energy into non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays are observed from the corona and chromosphere. Aims: We aim to characterize the acceleration…

Astrophysics · Physics 2009-11-11 Marina Battaglia , Arnold O. Benz

The energy released during solar flares is believed to be stored in non-potential magnetic fields associated with electric currents flowing in the corona. While no measurements of coronal electric currents are presently available, maps of…

Solar and Stellar Astrophysics · Physics 2015-08-19 Sophie Musset , Nicole Vilmer , Véronique Bommier

This paper reports on the re-analysis of solar flares in which the hard X-rays (HXRs) come predominantly from the corona rather than from the more usual chromospheric footpoints. All of the 26 previously analyzed event time intervals, over…

Solar and Stellar Astrophysics · Physics 2018-11-07 Brian R. Dennis , Miguel A. Duval-Poo , Michele Piana , Andrew R. Inglis , A. Gordon Emslie , Jingnan Guo , Yan Xu

We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities,…

The aim of this paper is to investigate the spatial structure of the impulsive phase hard X-ray emission from solar flares. This work is motivated by the YOHKOH and the forthcoming HESSI observations. Summarizing past results, it is shown…

Astrophysics · Physics 2009-10-31 Vahe Petrosian , Timothy Q. Donaghy

The hard X-ray emission in a solar flare is typically characterized by a number of discrete sources, each with its own spectral, temporal, and spatial variability. Establishing the relationship amongst these sources is critical to determine…

Solar and Stellar Astrophysics · Physics 2018-08-08 Federica Sciacchitano , Alberto Sorrentino , A Gordon Emslie , Anna Maria Massone , Michele Piana

The hard X-ray (HXR) emission in solar flares comes almost exclusively from a very small part of the flaring region, the footpoints of magnetic loops. Using RHESSI observations of solar flare footpoints, we determine the radial positions…

Solar and Stellar Astrophysics · Physics 2015-05-27 Marina Battaglia , Eduard P. Kontar

Context. We present an analysis of a GOES M1.8 flare with excellent observational coverage in UV, EUV, and X-ray, including observations from the instruments IRIS, SDO with AIA, Hinode/EIS, Hinode/XRT, and Solar Orbiter with the…

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