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Observational data require a rich variety of mechanisms to accelerate fast particles in astrophysical environments operating under different conditions. The mechanisms discussed in the literature include varying magnetic fields in compact…

High Energy Astrophysical Phenomena · Physics 2015-11-06 Elisabete M. de Gouveia Dal Pino , Grzegorz Kowal

Fast magnetic reconnection may occur in different astrophysical sources, producing flare-like emission and particle acceleration. Currently, this process is being studied as an efficient mechanism to accelerate particles via a first-order…

High Energy Astrophysical Phenomena · Physics 2016-10-26 M. V. del Valle , E. M. de Gouveia Dal Pino , G. Kowal

Fast particles are accelerated in astrophysical environments by a variety of processes. Acceleration in reconnection sites has attracted the attention of researchers recently. In this letter we analyze the energy distribution evolution of…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Grzegorz Kowal , Elisabete M. de Gouveia Dal Pino , Alex Lazarian

First-order Fermi acceleration processes at ultrarelativistic shocks are studied with Monte Carlo simulations. The accelerated particle spectra are obtained by integrating the exact particle trajectories in a turbulent magnetic field near…

Astrophysics · Physics 2009-11-13 Jacek Niemiec

First-order Fermi acceleration processes at ultrarelativistic shocks are studied with Monte Carlo simulations. The accelerated particle spectra are derived by integrating the exact particle trajectories in a turbulent magnetic field near…

Astrophysics · Physics 2009-11-13 Jacek Niemiec , Michal Ostrowski

This work provides a concrete implementation of E. Fermi's model of particle acceleration in magnetohydrodynamic (MHD) turbulence, connecting the rate of energization to the gradients of the velocity of magnetic field lines, which it…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Martin Lemoine

While a growing body of research indicates that relativistic magnetic reconnection is a prodigious source of particle acceleration in high-energy astrophysical systems, the dominant acceleration mechanism remains controversial. Using a…

High Energy Astrophysical Phenomena · Physics 2019-07-17 Fan Guo , Xiaocan Li , William Daughton , Patrick Kilian , Hui Li , Yi-Hsin Liu , Wangcheng Yan , Dylan Ma

First-order Fermi acceleration process at a relativistic shock wave is investigated by means of Monte Carlo simulations involving numerical integration of particle equations of motion in a turbulent magnetic field near the shock. In…

Astrophysics · Physics 2007-05-23 Jacek Niemiec , Michal Ostrowski

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 first-order Fermi acceleration process at an ultra-relativistic shock wave is expected to create a particle spectrum with the unique asymptotic spectral index sigma_{gamma >> 1} approximately 2.2. Below, we discuss this result and…

Astrophysics · Physics 2011-05-23 M. Ostrowski , J. Bednarz

Magnetic reconnection drives multi-species particle acceleration broadly in space and astrophysics. We perform the first 3D hybrid simulations (fluid electrons, kinetic ions) that contain sufficient scale separation to produce nonthermal…

Solar and Stellar Astrophysics · Physics 2024-01-31 Qile Zhang , Fan Guo , William Daughton , Hui Li , Ari Le , Tai Phan , Mihir Desai

The acceleration time scale for the process of first-order Fermi acceleration in relativistic shock waves with oblique magnetic field configurations is investigated by the method of Monte Carlo particle simulations. We demonstrate the…

Astrophysics · Physics 2015-06-24 J. Bednarz , M. Ostrowski

Numerical results for particle acceleration at multiple oblique shocks are presented. We calculate the steady state spectral slope of test particles accelerated by the first order Fermi process. The results are compared to analytical…

Astrophysics · Physics 2007-05-23 U. D. J. Gieseler , T. W. Jones

Context. Converging flows with strong magnetic fields of different polarity can accelerate particles through magnetic reconnection. If the particle mean free path is longer than the reconnection layer is thick, but much shorter than the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 V. Bosch-Ramon

The magnetic fields can change their topology through a process known as magnetic reconnection. This process in not only important for understanding the origin and evolution of the large-scale magnetic field, but is seen as a possibly…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Grzegorz Kowal , E. M. de Gouveia Dal Pino , A. Lazarian

Our numerical simulations show that the reconnection of magnetic field becomes fast in the presence of weak turbulence in the way consistent with the Lazarian and Vishniac (1999) model of fast reconnection. We trace particles within our…

Astrophysics of Galaxies · Physics 2015-05-18 A. Lazarian , G. Kowal , E. Vishniac , E. de Gouveia dal Pino

We simulate the acceleration processes of collisionless particles in a shock structure with magnetohydrodynamical (MHD) fluctuations. The electromagnetic field is represented as a sum of MHD shock solution ($\Mag_0, \Ele_0$) and torsional…

Astrophysics · Physics 2009-11-13 Takayuki Muranushi , Shu-ichiro Inutsuka

The theory of first order Fermi acceleration at shocks assumes that particles diffuse due to scattering off slow-moving magnetic irregularities. However, cosmic rays are closely tied to magnetic field lines, and the transport process,…

Astrophysics · Physics 2011-05-23 P. Duffy , J. G. Kirk , Y. A. Gallant , R. O. Dendy

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

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
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