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We present a multi-wavelength observation of a solar flare occurring on 2006 December 13 with Hinode, RHESSI, and the Nobeyama Radio Observatory, to study the electron acceleration site and mechanism. The Solar Optical Telescope (SOT) on…

Solar and Stellar Astrophysics · Physics 2010-01-15 T. Minoshima , S. Imada , T. Morimoto , T. Kawate , H. Koshiishi , M. Kubo , S. Inoue , H. Isobe , S. Masuda , S. Krucker , T. Yokoyama

Where particle acceleration and plasma heating take place in relation to magnetic reconnection is a fundamental question for solar flares. We report analysis of an M7.7 flare on 2012 July 19 observed by SDO/AIA and RHESSI. Bi-directional…

Solar and Stellar Astrophysics · Physics 2014-04-04 Wei Liu , Qingrong Chen , Vahe' Petrosian

Data from recent numerical simulations of the solar corona and transition region are analysed and the magnetic field connection between the low corona and the photosphere is found to be close to that of a potential field. The fieldline to…

Astrophysics · Physics 2014-10-13 B. V. Gudiksen , Å. Nordlund

Using {\em RHESSI} hard X-ray imaging spectroscopy observations, we analyze electron flux maps for a number of extended coronal loop flares. For each event, we fit a collisional model with an extended acceleration region to the observed…

Solar and Stellar Astrophysics · Physics 2015-06-05 Jingnan Guo , A. Gordon Emslie , Anna Maria Massone , Michele Piana

Recent measurements of vertical extents and positions of the chromospheric hard X-ray (HXR) flare sources based on Ramaty High-Energy Spectroscopic Imager (RHESSI) observations show a significant inconsistency with the theoretical…

Solar and Stellar Astrophysics · Physics 2016-12-07 Z. Moravec , M. Varady , J. Kasparova , D. Kramolis

Solar flares are one of the main forces behind space weather events. However the mechanism that drives such energetic phenomena is not fully understood. The standard eruptive flare model predicts that magnetic reconnection occurs high in…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Imada , K. Aoki , H. Hara , T. Watanabe , L. K. Harra , T. Shimizu

Gamma-rays and neutrons are the only sources of information on energetic ions present during solar flares and on properties of these ions when they interact in the solar atmosphere. The production of {\gamma}-rays and neutrons results from…

Solar and Stellar Astrophysics · Physics 2011-10-12 Nicole Vilmer , Alec L. MacKinnon , Gordon J. Hurford

We present detailed 3D modeling of a dense, coronal thick target X-ray flare using the GX Simulator tool, photospheric magnetic measurements, and microwave imaging and spectroscopy data. The developed model offers a remarkable agreement…

Solar and Stellar Astrophysics · Physics 2016-01-13 Gregory D. Fleishman , Yan Xu , Gelu N. Nita , Dale E. Gary

We present a detailed multi-wavelength analysis and interpretation of the evolution of an M7.6 flare on October 24, 2003. The X-ray observations of the flare taken from the RHESSI spacecraft reveal two phases of the flare evolution. The…

Recent detections of high-energy $\gamma$-rays from behind-the-limb (BTL) solar flares by the \emph{Fermi $\gamma$-ray Space Telescope} pose a puzzle and challenge on the particle acceleration and transport mechanisms. In such events, the…

Observational evidence is presented for the merging of a downward-propagating plasmoid with a looptop kernel during an occulted limb event on 2007 January 25. RHESSI lightcurves in the 9-18 keV energy range, as well as that of the 245 MHz…

Solar and Stellar Astrophysics · Physics 2015-05-18 Ryan O. Milligan , R. T. James McAteer , Brian R. Dennis , C. Alex Young

One of the main science questions of the Solar Orbiter and Parker Solar Probe missions deals with understanding how electrons in the lower solar corona are accelerated and how they subsequently access interplanetary space. We aim to…

Using a model of particle acceleration and transport in solar flares, we investigate the height distribution of coronal electrons by focusing on the energy-dependent pitch-angle scattering. When pitch-angle scattering is not included, the…

Solar and Stellar Astrophysics · Physics 2015-05-27 Takashi Minoshima , Satoshi Masuda , Yoshizumi Miyoshi , Kanya Kusano

Solar flares produce hard X-ray emission of which the photon spectrum is often represented by a combination of thermal and power-law distributions. However, the estimates of the number and total energy of non-thermal electrons are sensitive…

Solar and Stellar Astrophysics · Physics 2015-06-12 M. Oka , S. Ishikawa , P. Saint-Hilaire , S. Krucker , R. P. Lin

This Letter is to investigate the physics of a newly discovered phenomenon -- contracting flare loops in the early phase of solar flares. In classical flare models, which were constructed based on the phenomenon of expansion of flare loops,…

Astrophysics · Physics 2009-11-13 Jinhua Shen , Tuanhui Zhou , Haisheng Ji , Na Wang , Wenda Cao , Haimin Wang

This paper is an attempt to understand the physical processes occurring in different layers of solar atmosphere during a solar flare. For a complete understanding of the flare we must analyze multi-wavelength datasets, as emission at…

Solar and Stellar Astrophysics · Physics 2020-09-30 Shirsh Lata Soni , Radhe Shyam Gupta , Adya Prasad Mishra

We present the results of an analysis of hard X-ray observations of the C2.7 solar flare detected by the RT-2 Experiment onboard the Coronas - Photon satellite. We detect hard X-ray pulsations at periods of ~12 s and ~15 s. We find a…

Extending previous studies of nonthermal electron transport in solar flares which include the effects of collisional energy diffusion and thermalization of fast electrons, we present an analytic method to infer more accurate estimates of…

Solar and Stellar Astrophysics · Physics 2015-08-19 E. P. Kontar , N. L. S. Jeffrey , A. G. Emslie , N. H. Bian

We investigate the type III radio bursts and X-ray signatures of accelerated electrons in a well observed solar flare in order to find the spatial properties of the acceleration region. Combining simultaneous RHESSI hard X-ray flare data…

Solar and Stellar Astrophysics · Physics 2015-05-27 H. A. S. Reid , N. Vilmer , E. P. Kontar

The impulsive phase of a solar flare is known to generate strong turbulence and to transfer magnetic energy into accelerated electrons. Recognizing the importance of angular diffusion on the dynamics of the accelerated electrons, we extend…

Solar and Stellar Astrophysics · Physics 2026-03-30 A. Gordon Emslie , Eduard P. Kontar