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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

The acceleration of charged particles is relevant to the solar corona over a broad range of scales and energies. High-energy particles are usually detected in concomitance with large energy release events like solar eruptions and flares,…

Solar and Stellar Astrophysics · Physics 2014-02-27 S. Dalena , A. F. Rappazzo , P. Dmitruk , A. Greco , W. H. Matthaeus

The Fermi acceleration model was introduced to describe how cosmic ray particles are accelerated to great speeds by interacting with moving magnetic fields. We identify a new variation of the model where light ions interact with a moving…

Plasma Physics · Physics 2022-02-02 J. C. Waybright , M. E. Mlodik , N. J. Fisch

Initial results from simulations of 4-fluid MHD turbulence in molecular clouds are presented. The species included in the simulations are ions, electrons, negatively charged dust grains and neutrals. The results indicate that, on length…

Astrophysics of Galaxies · Physics 2012-08-02 Turlough P. Downes

Fermi acceleration in a Fermi-Ulam model, consisting of an ensemble of particles bouncing between two, infinitely heavy, stochastically oscillating hard walls, is investigated. It is shown that the widely used approximation, neglecting the…

Chaotic Dynamics · Physics 2009-11-11 A. K. Karlis , P. K. Papachristou , F. K. Diakonos , V. Constantoudis , P. Schmelcher

Stochastic particle acceleration in turbulent plasmas plays a key role in shaping high-energy emission from relativistic outflows, such as those in Active Galactic Nuclei (AGN) and microquasars. While traditional Fermi-II models provide a…

High Energy Astrophysical Phenomena · Physics 2026-03-11 Anton Dmytriiev , Frans van der Merwe , Markus Böttcher

MHD Turbulence is common in many space physics and astrophysics environments. We first discuss the properties of incompressible MHD turbulence. A well-conductive fluid amplifies initial magnetic fields in a process called small-scale…

Astrophysics of Galaxies · Physics 2015-06-19 Andrey Beresnyak , Alex Lazarian

Correlated many-fermion systems emerge in a broad range of phenomena in warm dense matter, plasmonics, and ultracold atoms. Quantum hydrodynamics (QHD) complements common first-principles methods for many-fermion systems and enables…

Plasma Physics · Physics 2022-02-17 Zh. A. Moldabekov , T. Dornheim , G. Gregori , F. Graziani , M. Bonitz , A. Cangi

We give a new coherent description of the first-order Fermi acceleration of particles in shock waves from the point of view of stochastic process of the individual particles, under the test particle approximation. The time development of…

Astrophysics · Physics 2009-11-07 Tsunehiko N. Kato , Fumio Takahara

In this paper we discuss recent applications of the Smoothed Particle Hydrodynamics (SPH) method to the simulation of supersonic turbulence in the interstellar medium, as well as giving an update on recent algorithmic developments in…

Instrumentation and Methods for Astrophysics · Physics 2010-02-26 Daniel J. Price , Christoph Federrath

The effect of compressibility in charged particle energization by magnetohydrodynamic (MHD) fields is studiedin the context of test particle simulations. This problem is relevant to the solar wind and the solar corona due to the…

Plasma Physics · Physics 2016-08-24 C. A. González , P. Dmitruk , P. D. Mininni , W. H. Matthaeus

We build on recent developments in the study of fluid turbulence [Gibbon \textit{et al.} Nonlinearity 27, 2605 (2014)] to define suitably scaled, order-$m$ moments, $D_m^{\pm}$, of $\omega^\pm= \omega \pm j$, where $\omega$ and $j$ are,…

Fluid Dynamics · Physics 2016-05-27 J. D. Gibbon , A. Gupta , G. Krstulovic , R. Pandit , H. Politano , Y. Ponty , A. Pouquet , G. Sahoo , J. Stawarz

Following the previous work of Ferretti and Yang on the role of magnetic fields in the theory of conformal turbulence, we show that non-unitary minimal model solutions to 2-dimensional magnetohydrodynamics (MHD) obtained by dimensional…

High Energy Physics - Theory · Physics 2015-06-26 Omduth Coceal , Steven Thomas

A new computational model is presented suitable for exploring the self-consistent production of energetic electrons during magnetic reconnection in macroscale systems. The equations are based on the recent discovery that parallel electric…

Solar and Stellar Astrophysics · Physics 2019-01-30 J. F. Drake , H. Arnold , M. Swisdak , J. T. Dahlin

We present high resolution numerical simulations of compressible magnetohydrodynamic (MHD) turbulence. We concentrate on studies of spectra and anisotropy of velocity and density. We describe a technique of separating different…

Astrophysics · Physics 2016-08-30 Jungyeon Cho , A. Lazarian

Here we investigate some aspects of stochastic acceleration of ultrarelativistic electrons by magnetic turbulence. In particular, we discuss the steady-state energy spectra of particles undergoing momentum diffusion due to resonant…

Astrophysics · Physics 2009-11-13 L. Stawarz , V. Petrosian

We introduce a Monte Carlo model of nonlinear diffusive shock acceleration allowing for the generation of large-amplitude magnetic turbulence. The model is the first to include strong wave generation, efficient particle acceleration to…

Astrophysics · Physics 2008-11-26 Andrey Vladimirov , Donald C. Ellison , Andrei Bykov

Magnetised plasma turbulence pervades the universe and is likely to play an important role in a variety of astrophysical settings. Magnetohydrodynamics (MHD) provides the simplest theoretical framework in which phenomenological models for…

Plasma Physics · Physics 2012-07-23 Joanne Mason , Jean C. Perez , Stanislav Boldyrev , Fausto Cattaneo

The rate at which particles are accelerated by the first-order Fermi mechanism in shocks depends on the angle, \teq{\Tbone}, that the upstream magnetic field makes with the shock normal. The greater the obliquity the greater the rate, and…

Astrophysics · Physics 2009-10-28 D. C. Ellison , M. G. Baring , F. C. Jones

It is believed that turbulence may have a significant impact on star formation and the dynamics and evolution of the molecular clouds in which this occurs. It is also known that non-ideal magnetohydrodynamic effects influence the nature of…

Astrophysics of Galaxies · Physics 2015-06-05 T. P. Downes
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