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The imaging spectroscopy capabilities of the Reuven Ramaty high energy solar spectroscopic imager (RHESSI) enable the examination of the accelerated electron distribution throughout a solar flare region. In particular, it has been revealed…

Solar and Stellar Astrophysics · Physics 2018-04-25 Duncan J. Stackhouse , Eduard P. Kontar

With the elementary energy release events introduced in a previous paper (Liu & Fletcher 2009) we model the chromospheric evaporation in flaring loops. The thick-target hard X-ray (HXR) emission produced by electrons escaping from the…

Solar and Stellar Astrophysics · Physics 2014-11-20 Siming Liu , Feiran Han , Lyndsay Fletcher

Observational aspects of solar flares relevant to the acceleration process of electrons and protons are reviewed and it is shown that most of these observations can be explained by the interaction with flare plasma of a power law energy…

Astrophysics · Physics 2007-05-23 Vahe Petrosian

The aim of this study is to generate maps of the hard X-ray emission produced by energetic electrons in a solar flare and compare them with observations. The ultimate goal is to test the viability of the combined MHD/test-particle approach…

Solar and Stellar Astrophysics · Physics 2020-11-04 Mykola Gordovskyy , Philippa K. Browning , Satoshi Inoue , Eduard P. Kontar , Kanya Kusano , Grigory E. Vekstein

During solar flares, a large flux of energetic electrons propagate from the tops of reconnecting magnetic flux tubes toward the lower atmosphere. Over the course of the electrons' transport, a co-spatial counter-streaming return current is…

Solar and Stellar Astrophysics · Physics 2021-08-25 Meriem Alaoui , Gordon D. Holman , Joel C. Allred , Rafael T. Eufrasio

Impulsive solar energetic electrons are often observed in the interplanetary space near the Earth and have an attractive diagnostic potential for poorly understood solar flare acceleration processes. We investigate the transport of solar…

Solar and Stellar Astrophysics · Physics 2009-11-13 E. P. Kontar , H. A. S. Reid

We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of…

Astrophysics · Physics 2009-11-13 T. Minoshima , T. Yokoyama , N. Mitani

We investigate the effects of acceleration during non-linear electron-beam relaxation in magnetized plasma in the case of electron transport in solar flares. The evolution of electron distribution functions is computed using a…

Solar and Stellar Astrophysics · Physics 2015-06-05 M. Karlicky , E. P. Kontar

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

A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and…

Astrophysics · Physics 2008-11-26 J. Kasparova , M. Karlicky , E. P. Kontar , R. A. Schwartz , B. R. Dennis

The angular distribution of electrons accelerated in solar flares is a key parameter in the understanding of the acceleration and propagation mechanisms that occur there. However, the anisotropy of energetic electrons is still a poorly…

Solar and Stellar Astrophysics · Physics 2012-12-24 Ewan Cameron Mackenzie Dickson , Eduard Kontar

We investigate whether the so-called kappa distribution, often used to fit electron distributions detected in-situ in the solar wind, can describe electrons producing the hard X-ray emission in solar flares. Using Ramaty High Energy Solar…

Solar and Stellar Astrophysics · Physics 2009-11-13 J. Kasparova , M. Karlicky

Recently, a number of peculiar flares have been reported, which demonstrate significant non-thermal particle signatures with a low, if any, thermal emission, that implies close association of the observed emission with the primary energy…

Sudden jets of collimated plasma arise from many locations on the Sun, including active regions. The magnetic field along which a jet emerges is often open to interplanetary space, offering a clear "escape route" for any flare-accelerated…

Solar and Stellar Astrophysics · Physics 2018-11-07 Lindsay Glesener , Gregory D. Fleishman

The solar corona is full of dynamic phenomena, e.g., solar flares, micro flares in active regions, jets in coronal holes and in the polar regions, X-ray bright points in quiet regions, etc. They are accompanied by interesting physical…

Solar and Stellar Astrophysics · Physics 2017-06-15 Noriyuki Narukage , Shin-nosuke Ishikawa , Tomoko Kawate , Shinsuke Imada , Taro Sakao

\textit{Extreme Ultraviolet Explorer} Deep Survey observations of cool stars (spectral type F to M) have been used to investigate the distribution of coronal flare rates in energy and its relation to activity indicators and rotation…

Astrophysics · Physics 2015-06-24 Marc Audard , Manuel Guedel , Jeremy J. Drake , Vinay L. Kashyap

In the standard model of solar flares, energy deposition by a beam of electrons drives strong chromospheric evaporation leading to a significantly denser corona and much brighter emission across the spectrum. Chromospheric evaporation was…

Solar and Stellar Astrophysics · Physics 2015-06-29 Jeffrey Reep , Stephen Bradshaw , David Alexander

Particle acceleration in solar flares remains an outstanding problem in solar physics. It is yet unclear which of the acceleration mechanisms dominates and how exactly is the excessive magnetic energy transferred to the nonthermal and other…

Solar and Stellar Astrophysics · Physics 2019-09-25 Alexander T. Altyntsev , Nataliia S. Meshalkina , Alexandra L. Lysenko , Gregory D. Fleishman

This paper extends our earlier work on the acceleration of low-energy electrons by plasma turbulence to include the effects of finite temperature of the plasma. We consider the resonant interaction of thermal electrons with the whole…

Astrophysics · Physics 2009-10-30 Julia Pryadko , Vahe Petrosian

To explain the high temperature of the corona, much attention has been paid to the distribution of energy in dissipation events. Indeed, if the event energy distribution is steep enough, the smallest, unobservable events could be the…

Solar and Stellar Astrophysics · Physics 2016-07-06 Vincent Joulin , Éric Buchlin , Jacques Solomon , Chloé Guennou