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Related papers: Cold Solar Flares I. Microwave Domain

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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

Solar flares effectively accelerate particles to non-thermal energies. These accelerated electrons are responsible for energy transport and subsequent emissions in HXR, radio, and UV/EUV radiation. Due to the steeply decreasing electron…

Solar and Stellar Astrophysics · Physics 2026-01-01 Yingjie Luo , Eduard P. Kontar , Debesh Bhattacharjee

Low-energy protons entering the field of view of the XMM-Newton telescope scatter with the X-ray mirror surface and might reach the X-ray detectors on the focal plane. They manifest in the form of a sudden increase in the rates, usually…

High Energy Astrophysical Phenomena · Physics 2025-01-31 T. Mineo , V. Fioretti , S. Lotti , S. Molendi , G. Lanzuisi , M. Cappi , M. Dadina , S. Ettori , F. Gastaldello , R. Amato

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…

Understanding nonthermal particle generation, transport, and escape in solar flares requires detailed quantification of the particle evolution in the realistic 3D domain where the flare takes place. Rather surprisingly, apart of standard…

Solar and Stellar Astrophysics · Physics 2018-05-23 Gregory D. Fleishman , Gelu M. Nita , Natsuha Kuroda , Sabina Jia , Kevin Tong , Richard R. Wen , Zhou Zhizhuo

The standard flare model, despite its success, is limited in comprehensively explaining the various processes involving nonthermal particles. One such missing ingredient is a detailed understanding of the various processes involved during…

Solar and Stellar Astrophysics · Physics 2024-04-23 Surajit Mondal , Andrea F. Battaglia , Bin Chen , Sijie Yu

We have performed microwave diagnostics of the magnetic field strengths in solar flare loops based on the theory of gyrosynchrotron emission. From Nobeyama Radioheliograph observations of three flare events at 17 and 34 GHz, we obtained the…

Solar and Stellar Astrophysics · Physics 2020-06-30 Rui Zhu , Baolin Tan , Yingna Su , Hui Tian , Yu Xu , Xingyao Chen , Yongliang Song , Guangyu Tan

We report high-resolution observations at mid-infrared wavelengths of a minor solar flare, SOL2014-09-24T17T17:50 (C7.0), using Quantum Well Infrared Photodetector (QWIP) cameras at an auxiliary of the McMath-Pierce telescope. The flare…

Solar and Stellar Astrophysics · Physics 2016-03-23 M Penn , S Krucker , H Hudson , M Jhabvala , D Jennings , A Lunsford , P Kaufmann

We present radio and X-ray observations of an impulsive solar flare that was moderately intense in microwaves, yet showed very meager EUV and X-ray emission. The flare occurred on 2001 Oct 24 and was well-observed at radio wavelengths by…

Astrophysics · Physics 2009-06-23 T. S. Bastian , G. D. Fleishman , D. E. Gary

We report solar flare plasma to be multi-thermal in nature based on the theoretical model and study of the energy-dependent timing of thermal emission in ten M-class flares. We employ high-resolution X-ray spectra observed by the Si…

Solar and Stellar Astrophysics · Physics 2011-03-30 Rajmal Jain , Arun Kumar Awasthi , Arvind Singh Rajpurohit , Markus J. Aschwanden

Solar flares are highly energetic events that happen in the solar atmosphere. They are mostly observed as X-ray or gamma-ray bursts located on the Sun's surface. While they are known to be sites of particle acceleration, the acceleration…

Solar and Stellar Astrophysics · Physics 2023-10-25 Jonathan Mauro , Gwenhaël de Wasseige

In this article, we measure the mean magnetic shear from the morphological evolution of flare ribbons, and examine the evolution of flare thermal and non-thermal X-ray emissions during the progress of flare reconnection. We analyze three…

Solar and Stellar Astrophysics · Physics 2022-07-20 Jiong Qiu , Jianxia Cheng

Solar flare hard X-ray spectroscopy serves as a key diagnostic of the accelerated electron spectrum. However, the standard approach using the collisional cold thick-target model poorly constrains the lower-energy part of the accelerated…

Solar and Stellar Astrophysics · Physics 2019-02-05 Eduard P. Kontar , Natasha L. S. Jeffrey , A. Gordon Emslie

White light flares (WLFs) are observational rarities, making them understudied events. However, optical emission is a significant contribution to flare energy budgets and the emission mechanisms responsible could have important implications…

Solar and Stellar Astrophysics · Physics 2015-06-18 Graham Stewart Kerr , Lyndsay Fletcher

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…

Flares are short-lived but energetic manifestations of stellar activity. Studying them is crucial, as they emit intense high-energy radiation that can impact the circumstellar environment, especially the atmospheres of orbiting planets.…

Solar and Stellar Astrophysics · Physics 2025-05-22 G. Galletta , S. Colombo , L. Prisinzano , G. Micela

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 disparate nature of thermal-nonthermal energy partition during flares, particularly during weak flares, is still an open issue. Following the Neupert effect, quantifying the relative yield of X-ray emission in different energy bands can…

Solar and Stellar Astrophysics · Physics 2024-02-06 Arun Kumar Awasthi , Tomasz Mrozek , Sylwester Kołomański , Michalina Litwicka , Marek Stęślicki , Karol Kułaga

The study aims to examine the spectral dynamics of the low-frequency, optically thick gyrosynchrotron microwave emission in solar flares to determine the characteristics of the emitting source. We present the high-resolution spectra of a…

Solar and Stellar Astrophysics · Physics 2021-09-29 Shaheda Begum Shaik , Dale E. Gary

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
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