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We show how the conversion of magnetic field energy via magnetic reconnection can progress in a fully three-dimensional, fast, volume-filling regime. An initial configuration representative of many laboratory, space and astrophysical…

Solar and Stellar Astrophysics · Physics 2015-05-27 Giovanni Lapenta , Lapo Bettarini

Particle acceleration and magnetic field amplification in relativistic shocks propagating in inhomogeneous media are investigated by three-dimensional magnetohydrodynamical (MHD) simulations and test-particle simulations. The MHD…

High Energy Astrophysical Phenomena · Physics 2024-06-27 Kanji Morikawa , Yutaka Ohira , Takumi Ohmura

Charged particles scattering on moving inhomogenities of the magnetised interstellar medium can gain energy through the process of second-order Fermi acceleration. This energy gain depletes in turn the magnetic wave spectrum around the…

High Energy Astrophysical Phenomena · Physics 2020-10-14 M. Kachelriess , J. Tjemsland

This paper presents numerical simulations of test particle Fermi acceleration at relativistic shocks of Lorentz factor Gamma_sh = 2-60, using a realistic downstream magnetic structure obtained from the shock jump conditions. The upstream…

Astrophysics · Physics 2009-11-13 Martin Lemoine , Benoit Revenu

Nonthermal relativistic plasmas are ubiquitous in astrophysical systems like pulsar wind nebulae and active galactic nuclei, as inferred from their emission spectra. The underlying nonthermal particle acceleration (NTPA) processes have…

High Energy Astrophysical Phenomena · Physics 2020-04-15 Kai Wong , Vladimir Zhdankin , Dmitri A. Uzdensky , Gregory R. Werner , Mitchell C. Begelman

In an idealized system where four current channels interact in a two-dimensional periodic setting, we follow the detailed evolution of current sheets (CSs) forming in between the channels, as a result of a large-scale merging. A central…

Solar and Stellar Astrophysics · Physics 2021-10-04 Xiaozhou Zhao , Fabio Bacchini , Rony Keppens

We study the effects of turbulence on magnetic reconnection using three-dimensional numerical simulations. This is the first attempt to test a model of fast magnetic reconnection proposed by Lazarian & Vishniac (1999), which assumes the…

Astrophysics · Physics 2008-12-12 G. Kowal , A. Lazarian , E. T. Vishniac , K. Otmianowska-Mazur

We present a new algorithm for the identification and physical characterization of current sheets and reconnection sites in 2D and 3D large scale relativisticmagnetohydrodynamic numerical simulations. This has been implemented in the PLUTO…

High Energy Astrophysical Phenomena · Physics 2023-05-29 Matteo Nurisso , Annalisa Celotti , Andrea Mignone , Gianluigi Bodo

First order Fermi acceleration at astrophysical shocks is often invoked as a mechanism for the generation of non-thermal particles. This mechanism is especially simple in the approximation that the accelerated particles behave like test…

Astrophysics · Physics 2015-06-24 Pasquale Blasi

We analyze the transport properties of charged particles (ions and electrons) interacting with randomly formed magnetic scatterers (e.g.\ large scale local ``magnetic fluctuations'' or ``coherent magnetic irregularities'' usually present in…

Solar and Stellar Astrophysics · Physics 2020-01-08 Nikos Sioulas , Heinz Isliker , Loukas Vlahos , Argyris Koumtzis , Theophilos Pisokas

Turbulent high-energy astrophysical systems often feature asymmetric energy injection: for instance, Alfven waves propagating from an accretion disk into its corona. Such systems are "imbalanced": the energy fluxes parallel and…

High Energy Astrophysical Phenomena · Physics 2021-12-22 Amelia Hankla , Vladimir Zhdankin , Gregory Werner , Dmitri Uzdensky , Mitchell Begelman

Magnetic reconnection plays an essential role in the generation and evolution of astrophysical magnetic fields. The best tested and most robust reconnection theory is that of Parker and Sweet. According to this theory, the reconnection rate…

Astrophysics · Physics 2009-11-07 Fabian Heitsch , Ellen G. Zweibel

Magnetic reconnection is a ubiquitous process in astrophysical plasmas and an efficient mechanism for particle acceleration. Using 2.5D magnetohydrodynamic (MHD) simulations with a co-evolving fluid-particle framework, we investigate how…

Plasma Physics · Physics 2026-01-01 Shimin Liang , Nianyu Yi

We examine the first order Fermi acceleration on the presumption that supernova remnant shocks cross ambient magnetic fields with various angles. These oblique shocks accelerate particles more efficiently than the parallel shocks and…

Astrophysics · Physics 2009-10-31 K. Kobayakawa , Y. S. Honda , T. Samura

The diffusion of astrophysical magnetic fields in conducting fluids in the presence of turbulence depends on whether magnetic fields can change their topology or reconnect in highly conducting media. Recent progress in understanding fast…

Astrophysics of Galaxies · Physics 2010-03-16 A. Lazarian , R. Santos-Lima , E. Gouveia Dal Pino

An oblique-rotating pulsar generates a relativistic striped wind in a pulsar wind nebula (PWN). The termination shock of the PWN compresses the Poynting-flux-dominated flow and drives magnetic reconnection. By carrying out particle-in-cell…

High Energy Astrophysical Phenomena · Physics 2021-03-03 Yingchao Lu , Fan Guo , Patrick Kilian , Hui Li , Chengkun Huang , Edison Liang

We investigate the influence of coherent structures on particle acceleration in the strongly turbulent solar corona. By randomizing the Fourier phases of a pseudo-spectral simulation of isotropic MHD turbulence (Re $\sim 300$), and tracing…

Astrophysics · Physics 2009-11-13 Kaspar Arzner , Bernard Knaepen , Daniele Carati , Nicolas Denewet , Loukas Vlahos

Fermi acceleration can take place at ultra-relativistic shock waves if the upstream or downstream magnetic field has been remodeled so that most of the magnetic power lies on short spatial scales. The relevant conditions under which Fermi…

Astrophysics · Physics 2009-11-13 Guy Pelletier , Martin Lemoine , Alexandre Marcowith

It has been established that the Sweet-Parker current layer in high Lundquist number reconnection is unstable to the super-Alfv\'enic plasmoid instability. Past two-dimensional magnetohydrodynamic simulations have demonstrated that the…

Plasma Physics · Physics 2016-02-17 Yi-Min Huang , A. Bhattacharjee

The generic acceleration model for ultra high energy cosmic rays, which has been introduced in {\tt 1006.5708 [astro-ph.HE]}, suggests various types of electromagnetic interactions between cosmic charged particles and the different types of…

High Energy Astrophysical Phenomena · Physics 2014-03-18 A. Tawfik , A. Saleh