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We discuss the phenomenon of energization of relativistic charged particles in three-dimensional (3D) incompressible MHD turbulence and the diffusive properties of the motion of the same particles. We show that the random electric field…

High Energy Astrophysical Phenomena · Physics 2022-04-05 Oreste Pezzi , Pasquale Blasi , William H. Matthaeus

To use a 3D numerical MHD experiment representing magnetic flux emerging into an open field region as a background field for tracing charged particles. The interaction between the two flux systems generates a localised current sheet where…

Solar and Stellar Astrophysics · Physics 2015-05-18 Karl Joakim Rosdahl , Klaus Galsgaard

Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy…

Solar and Stellar Astrophysics · Physics 2017-08-09 R. Lionello , T. TÖrÖk , V. S. Titov , J. E. Leake , Z. MikiĆ , J. A. Linker , M. G. Linton

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

Energetic particles that undergo strong pitch-angle scattering and diffuse through a plasma containing strong compressible MHD turbulence undergo diffusion in momentum space with diffusion coefficient Dp. In this paper, the contribution of…

Astrophysics · Physics 2009-11-10 Benjamin D. G. Chandran

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

Stochastic acceleration of charged particles due to interactions with magnetohydrodynamic (MHD) plasma waves is the dominant process leading to the formation of the high-energy electron and ion distributions in a variety of astrophysical…

Astrophysics · Physics 2008-11-26 P. A. Becker , T. Le , C. D. Dermer

Particle transport, acceleration and energisation are phenomena of major importance for both space and laboratory plasmas. Despite years of study, an accurate theoretical description of these effects is still lacking. Validating models with…

The source of high-energy protons (>500 MeV) responsible for the so-called ground level enhancements (GLEs) remains an open question in solar physics. One of the candidates is a shock wave driven by a coronal mass ejection, which is thought…

Solar and Stellar Astrophysics · Physics 2018-06-15 A. Afanasiev , R. Vainio , A. P. Rouillard , M. Battarbee , A. Aran , P. Zucca

We investigate the processes that lead to the formation, ejection and fall of a confined plasma ejection that was observed in a numerical experiment of the solar corona. By quantifying physical parameters such as mass, velocity, and…

Solar and Stellar Astrophysics · Physics 2015-05-28 P. Zacharias , H. Peter , S. Bingert

We discuss possible mechanisms of acceleration of particles in solar flares and show that turbulence plays an important role in all the mechanism. It is also argued that stochastic particle acceleration by turbulent plasma waves is the most…

Astrophysics · Physics 2008-08-14 Vahe' Petrosian

In solar flares and other astrophysical systems, a major challenge for solving particle acceleration problem associated with magnetic reconnection is the enormous scale separation between kinetic scales and observed reconnection scale.…

Solar and Stellar Astrophysics · Physics 2018-10-08 Xiaocan Li , Fan Guo , Hui Li , Shengtai Li

Long-time high-resolution simulations of the dynamics of a coronal loop in cartesian geometry are carried out, within the framework of reduced magnetohydrodynamics (RMHD), to understand coronal heating driven by motion of field lines…

Astrophysics · Physics 2008-11-26 A. F. Rappazzo , M. Velli , G. Einaudi , R. B. Dahlburg

We present numerical modelling of particle acceleration at coronal shocks propagating through a streamer-like magnetic field by solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show…

Solar and Stellar Astrophysics · Physics 2019-09-25 Xiangliang Kong , Fan Guo , Yao Chen , Joe Giacalone

Context. The magnetic field in the solar atmosphere continually reconnects and accelerates charged particles to high energies. Simulations of the atmosphere in three dimensions that include the effects of accelerated particles can aid our…

Solar and Stellar Astrophysics · Physics 2022-10-05 L. Frogner , B. V. Gudiksen

The acceleration of protons and electrons to high (sometimes GeV/nucleon) energies by solar phenomena is a key component of space weather. These solar energetic particle (SEP) events can damage spacecraft and communications, as well as…

Microparticles ranging from sub-microns to millimeter in size are a common form of matter in magnetic fusion environment, and they are highly mobile due to their small mass. Different forces in addition to gravity can affect their motion…

Instrumentation and Detectors · Physics 2018-08-01 Pinghan Chu , Bradley T. Wolfe , Zhehui Wang

We establish a classification scheme for stochastic acceleration models involving low-frequency plasma turbulence in a strongly magnetized plasma. This classification takes into account both the properties of the accelerating…

Solar and Stellar Astrophysics · Physics 2015-06-05 Nicolas Bian , A. Gordon Emslie , Eduard P. Kontar

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

Magnetohydrodynamic (MHD) turbulence is a ubiquitous dynamical state of astrophysical plasmas and a primary agent in the redistribution, dissipation, and conversion of energy into particle populations. Yet turbulence is still most often…

High Energy Astrophysical Phenomena · Physics 2026-04-21 Loukas Vlahos