English
Related papers

Related papers: Particle acceleration at ultrarelativistic, perpen…

200 papers

Supernova remnants are expected to contain braided (or stochastic) magnetic fields, which are in some regions directed mainly perpendicular to the shock normal. For particle acceleration due to repeated shock crossings, the transport in the…

Astrophysics · Physics 2007-05-23 U. D. J. Gieseler , J. G. Kirk

Relativistic current sheets have been proposed as the sites of dissipation in pulsar winds, jets in active galaxies and other Poynting-flux dominated flows. It is shown that the steady versions of these structures differ from their…

Astrophysics · Physics 2009-11-10 J. G. Kirk

A stochastic model is proposed for the acceleration of non-relativistic particles yielding to energy spectra with a shape of a Weibull\textquoteright s function. Such particle distribution is found as the stationary solution of a…

Space Physics · Physics 2016-02-23 G. Pallocchia , M. Laurenza , G. Consolini

We study diffusive shock acceleration (DSA) of electrons in non-relativistic quasi-perpendicular shocks using self-consistent one-dimensional particle-in-cell (PIC) simulations. By exploring the parameter space of sonic and Alfv\'{e}nic…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Rui Xu , Anatoly Spitkovsky , Damiano Caprioli

Magnetic reconnection in the relativistic and trans-relativistic regimes is able to accelerate particles to hard power law energy spectra $f \propto \gamma^{-p}$ (approaching $p=1$). The underlying acceleration mechanism that determines the…

High Energy Astrophysical Phenomena · Physics 2020-09-02 Patrick Kilian , Xiaocan Li , Fan Guo , Hui Li

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

We use large hybrid (kinetic protons-fluid electrons) simulations to investigate the transport of energetic particles in self-consistent electromagnetic configurations of collisionless shocks. In previous papers of this series, we showed…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Damiano Caprioli , Anatoly Spitkovsky

The analytical theory of diffusive cosmic ray acceleration at parallel stationary shock waves with magnetostatic turbulence is generalized to arbitrary shock speeds $V_s=\beta_1c$, including in particular relativistic speeds. This is…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Reinhard Schlickeiser

Thermal electrons cannot directly participate in the process of diffusive acceleration at electron-ion shocks because their Larmor radii are smaller than the shock transition width: this is the well-known electron injection problem of…

High Energy Astrophysical Phenomena · Physics 2022-06-29 Mohamad Shalaby , Rouven Lemmerz , Timon Thomas , Christoph Pfrommer

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

Plasma instabilities (e.g., Buneman, Weibel and other two-stream instabilities) created in collisionless shocks may be responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle…

Astrophysics · Physics 2009-11-13 K. -I. Nishikawa , P. E. Hardee , C. B. Hededal , G. J. Fishman

Recent experimental and theoretical results have demonstrated the possibility of accelerating electrons in the MeV range by focusing tightly a few-cycle laser beam in ambient air. Using Particle-In-Cell (PIC) simulations, this configuration…

After a successful development of theoretical and numerical works on Fermi acceleration at relativistic shocks, some difficulties recently raised with the scattering issue, a crucial aspect of the process. Most pioneering works were…

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

These notes present the fundamentals of Fermi acceleration at shocks, with a special attention to the role that supernova remnants have in producing Galactic cosmic rays. Then, the recent discoveries in the theory of diffusive shock…

High Energy Astrophysical Phenomena · Physics 2023-10-09 Damiano Caprioli

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 shown that an ultrarelativistic shock with the Lorentz factor of order of tens or higher propagating in a moderately dense interstellar medium (density above $\sim 1000 $ cm$^{-3}$) undergoes a fast dramatic transformation into a…

Astrophysics · Physics 2009-11-07 Boris E. Stern

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

A particle acceleration mechanism by radiation pressure of precursor waves in a relativistic shock is studied. For a relativistic, perpendicular shock with the upstream bulk Lorentz factor of $\gamma_1 \gg 1$, large amplitude…

Astrophysics · Physics 2009-11-13 Masahiro Hoshino

In-situ spacecraft observations recently suggested that the transport of energetic particles accelerated at heliospheric shocks can be anomalous, i.e. the mean square displacement can grow non-linearly in time. In particular, a new analysis…

Solar and Stellar Astrophysics · Physics 2015-06-01 Silvia Perri , Gaetano Zimbardo , Frederic Effenberger , Horst Fichtner

We propose the particle acceleration model coupled with multiple plasmoid ejections in a solar flare. Unsteady reconnection produces plasmoids in a current sheet and ejects them out to the fast shocks, where particles in a plasmoid are…

High Energy Astrophysical Phenomena · Physics 2015-06-12 N. Nishizuka , K. Shibata