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Related papers: Elementary Energy Release Events in Solar Flares

200 papers

Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect…

Solar and Stellar Astrophysics · Physics 2023-10-09 Ross Pallister , Natasha L. S. Jeffrey

We study the acceleration in solar flares of $^3$He and $^4$He from a thermal background by parallel propagating plasma waves with a general broken power-law spectrum that takes into account the turbulence generation processes at large…

Astrophysics · Physics 2016-08-16 Siming Liu , Vahé Petrosian , Glenn M. Mason

It is thought that solar energetic ions associated with coronal/interplanetary shock waves are accelerated to high energies by the diffusive shock acceleration mechanism. For this mechanism to be efficient, intense magnetic turbulence is…

Solar and Stellar Astrophysics · Physics 2023-11-29 A. Afanasiev , R. Vainio , D. Trotta , S. Nyberg , N. Talebpour Sheshvan , H. Hietala , N. Dresing

Solar flares show remarkable variety of the energy partitioning between thermal and nonthermal components. Those with a prominent nonthermal component but only a modest thermal one are particularly well suited to study the direct effect of…

Solar and Stellar Astrophysics · Physics 2020-02-26 Galina G. Motorina , Gregory D. Fleishman , Eduard P. Kontar

Solar flare accelerated electron beams propagating away from the Sun can interact with the turbulent interplanetary media, producing plasma waves and type III radio emission. These electron beams are detected near the Earth with a double…

Solar and Stellar Astrophysics · Physics 2015-05-19 H. A. S. Reid , E. P. Kontar

Solar flares release magnetic energy through reconnection, accelerating electrons into nonthermal velocity distributions, including crescent-shaped electron populations. These energetic electron distributions are crucial in driving…

Solar and Stellar Astrophysics · Physics 2025-01-08 Mehdi Yousefzadeh

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

Solar flares are large-scale releases of energy in the solar atmosphere, which are characterised by rapid changes in the hydrodynamic properties of plasma from the photosphere to the corona. Solar physicists have typically attempted to…

Solar and Stellar Astrophysics · Physics 2012-06-26 S. Adamakis , C. L. Raftery , R. W. Walsh , P. T. Gallagher

In a collisionless plasma, the energy distribution function of plasma particles can be strongly affected by turbulence. In particular, it can develop a non-thermal power-law tail at high energies. We argue that turbulence with initially…

Plasma Physics · Physics 2022-01-19 Cristian Vega , Stanislav Boldyrev , Vadim Roytershteyn , Mikhail Medvedev

A major open issue concerning the active Sun is the effectiveness with which magnetic reconnection accelerates electrons in flares. A paper published by {\em{Nature}} in 2022 used microwave observations to conclude that the Sun is an almost…

Solar and Stellar Astrophysics · Physics 2025-02-10 Anna Volpara , Paolo Massa , Michele Piana , Anna Maria Massone , A Gordon Emslie

Particle acceleration consequences from fluctuating electric fields superposed on an X-type magnetic field in collisionless solar plasma are studied. Such a system is chosen to mimic generic features of dynamic reconnection, or the…

Astrophysics · Physics 2009-11-13 P. Petkaki , A. L. MacKinnon

The propagation of solar energetic particles (SEPs) in interplanetary space is modulated by solar wind turbulence, which significantly influences particle diffusion and energy evolution through scattering processes. Traditional analyses…

Space Physics · Physics 2026-05-05 Yihang Cao , Jingnan Guo , Yuming Wang , Zhuxuan Zou , Yongjie Zhang , Cunhui Li

Turbulence is a predominant process for energizing electrons and ions in collisionless astrophysical plasmas, and thus is responsible for shaping their radiative signatures (luminosity, spectra, and variability). To better understand the…

High Energy Astrophysical Phenomena · Physics 2021-02-24 Vladimir Zhdankin , Dmitri A. Uzdensky , Matthew W. Kunz

High energy electrons carry much of a solar flare's energy. Therefore, understanding changes in electron beam distributions during their propagation is crucial. A key focus of this paper is how the co-spatial return current reduces the…

Solar and Stellar Astrophysics · Physics 2024-07-26 Meriem Alaoui , Gordon D. Holman , Marc Swisdak

Possible entropy constraints on particle acceleration spectra are discussed. Solar flare models invoke a variety of initial distributions of the primary energy release over the particles of the flare plasma -- ie., the partition of the…

Astrophysics · Physics 2011-05-23 John C Brown , Gregory Beekman , Norman Gray , Alexander L MacKinnon

Extreme ultraviolet (EUV) solar flare emissions evolve in time as the emitting plasma heats and then cools. Although accurately modeling this evolution has been historically difficult, especially for empirical relationships, it is important…

Solar and Stellar Astrophysics · Physics 2017-11-28 Edward M. B. Thiemann , Francis G. Eparvier , Thomas N. Woods

We present an ordinary case in the momentum diffusion equation for the electron spectrum evolution and investigate the energy spectra and time dependent properties of flare in Mrk 421 in the frame of a time-dependent one-zone synchrotron…

High Energy Astrophysical Phenomena · Physics 2016-08-02 Y. G. Zheng , S. J. Kang , J. Li

Driven by recent RHESSI observations of confined loop-top hard X-ray sources in solar flares, we consider stochastic acceleration of electrons in the presence of Coulomb collisions. If electron escape from the acceleration region can be…

Solar and Stellar Astrophysics · Physics 2015-06-23 Nicolas H. Bian , A. Gordon Emslie , Duncan J. Stackhouse , Eduard P. Kontar

In the full-orbit particle simulations of energetic particle transport in plasmas, the plasma turbulence is typically described as a homogeneous superposition of linear Fourier modes. The turbulence evolution is, however, typically a…

Solar and Stellar Astrophysics · Physics 2012-04-03 Timo Laitinen , Silvia Dalla , James Kelly

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