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Related papers: Rapid Variability in the SOL2011-08-04 Flare: Impl…

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We develop a model for stochastic acceleration of electrons in solar flares. As in several previous models, the electrons are accelerated by turbulent fast magnetosonic waves ("fast waves") via transit-time-damping (TTD) interactions. (In…

Solar and Stellar Astrophysics · Physics 2015-06-19 Peera Pongkitiwanichakul , Benjamin D. G. Chandran

Plasma turbulence is thought to be associated with various physical processes involved in solar flares, including magnetic reconnection, particle acceleration and transport. Using Ramaty High Energy Solar Spectroscopic Imager ({\it RHESSI})…

Solar and Stellar Astrophysics · Physics 2015-05-27 E. P. Kontar , I. G. Hannah , N. H. Bian

Solar flares are powerful particle accelerators, and in the accepted standard flare model most of the flare energy is transported from a coronal energy-release region by accelerated electrons which stop collisionally in the chromosphere,…

Solar and Stellar Astrophysics · Physics 2024-06-18 Paulo J. A. Simões , Lyndsay Fletcher , Hugh S. Hudson , Graham S. Kerr , Matt Penn , Karla F. Lopez

Solar flares - the most powerful explosions in the solar system - are also efficient particle accelerators, capable of energizing a large number of charged particles to relativistic speeds. A termination shock is often invoked in the…

Solar and Stellar Astrophysics · Physics 2015-12-09 Bin Chen , Timothy S. Bastian , Chengcai Shen , Dale E. Gary , Sam Krucker , Lindsay Glesener

We investigate the acceleration of charged particles (both electrons and protons) at collisionless shocks predicted to exist in the vicinity of solar flares. The existence of standing termination shocks has been examined by flare models and…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Fan Guo , Joe Giacalone

In some flares the thermal component appears much earlier than the nonthermal component in X-ray range. Using sensitive microwave observations we revisit this finding made by Battaglia et al. (2009) based on RHESSI data analysis. We have…

Solar and Stellar Astrophysics · Physics 2015-06-11 Alexander A. Altyntsev , Gregory D. Fleishman , Sergey V. Lesovoi , Natalia S. Meshalkina

We study the solar energetic particle (SEP) event observed on 9 October 2021, by multiple spacecraft including Solar Orbiter (SolO). The event was associated with an M1.6 flare, a coronal mass ejection (CME) and a shock wave. During the…

During a solar flare, electrons are accelerated to non-thermal energies as a result of magnetic reconnection. These electrons then propagate upwards and downwards from the energy release site along magnetic field lines and produce radio and…

Solar and Stellar Astrophysics · Physics 2025-03-04 Shilpi Bhunia , Laura A. Hayes , Karl Ludwig Klein , Nicole Vilmer , Shane A. Maloney , Peter T. Gallagher

Solar flare electron acceleration is an extremely efficient process, but the method of acceleration is not well constrained. Two of the essential diagnostics: electron anisotropy (velocity angle to the guiding magnetic field) and the high…

Solar and Stellar Astrophysics · Physics 2020-12-21 Natasha L. S. Jeffrey , Pascal Saint-Hilaire , Eduard P. Kontar

Even small solar flares can display a surprising level of complexity regarding their morphology and temporal evolution. Many of their properties, such as energy release and electron acceleration can be studied using highly complementary…

Solar and Stellar Astrophysics · Physics 2021-12-08 Marina Battaglia , Rohit Sharma , Yingjie Luo , Bin Chen , Sijie Yu , Säm Krucker

We analyze electron flux maps based on RHESSI hard X-ray imaging spectroscopy data for a number of extended coronal loop flare events. For each event, we determine the variation of the characteristic loop length $L$ with electron energy…

Solar and Stellar Astrophysics · Physics 2015-06-15 Jingnan Guo , A. Gordon Emslie , Michele Piana

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

Acceleration and transport of high-energy particles and fluid dynamics of atmospheric plasma are interrelated aspects of solar flares. We present here self-consistently combined Fokker-Planck modeling of particles and hydrodynamic…

Solar and Stellar Astrophysics · Physics 2009-09-28 Wei Liu , Vahe Petrosian , John T. Mariska

Nonthermal loop-top sources in solar flares are the most prominent observational signature that suggests energy release and particle acceleration in the solar corona. Although several scenarios for particle acceleration have been proposed,…

Solar and Stellar Astrophysics · Physics 2020-01-08 Xiangliang Kong , Fan Guo , Chengcai Shen , Bin Chen , Yao Chen , Sophie Musset , Lindsay Glesener , Peera Pongkitiwanichakul , Joe Giacalone

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

We propose a nonlinear self-consistent model of the turbulent non-resonant particle acceleration in solar flares. We simulate temporal evolution of the spectra of charged particles accelerated by strong long-wavelength MHD turbulence taking…

Solar and Stellar Astrophysics · Physics 2009-11-13 A. M. Bykov , G. D. Fleishman

An X3.4 solar flare and a fast halo coronal mass ejection (CME) occurred on 2006 December 13, accompanied by a high flux of energetic particles recorded both in near-Earth space and at ground level. Our purpose is to provide evidence of…

Solar and Stellar Astrophysics · Physics 2013-05-27 C. Li , Y. Dai , J. -C. Vial , C. J. Owen , S. A. Matthews , Y. H. Tang , C. Fang , A. N. Fazakerley

An electron distribution with a temperature anisotropy T_par/T_perp > 1 can lead to the Electron Firehose instability (Here par and perp denote directions relative to the background magnetic field B_0). Since possible particle acceleration…

Astrophysics · Physics 2007-05-23 Gunnar Paesold , Arnold O. Benz

We propose a new two-stage model for acceleration of electrons in solar flares. In the first stage, electrons are accelerated stochastically in a post-reconnection turbulent downflow. The second stage is the reprocessing of a subset of…

Astrophysics · Physics 2008-11-26 Robert Selkowitz , Eric G. Blackman

Context. We introduce a model for including accelerated particles in pure magnetohydrodynamics (MHD) simulations of the solar atmosphere. Aims. We show that the method is viable and produces results that enhance the realism of MHD…

Solar and Stellar Astrophysics · Physics 2018-12-05 Helle Bakke , Lars Frogner , Boris Vilhelm Gudiksen