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Electrons can be accelerated to ultrarelativistic energies at strong (high-Mach number) collisionless shock waves that form when stellar debris rapidly expands after a supernova. Collisionless shock waves also form in the flow of particles…

High Energy Astrophysical Phenomena · Physics 2015-06-12 A. Masters , L. Stawarz , M. Fujimoto , S. J. Schwartz , N. Sergis , M. F. Thomsen , A. Retinò , H. Hasegawa , G. R. Lewis , A. J. Coates , P. Canu , M. K. Dougherty

Fast collisionless shocks in cosmic plasmas convert their kinetic energy flow into the hot downstream thermal plasma with a substantial fraction of energy going into a broad spectrum of superthermal charged particles and magnetic…

High Energy Astrophysical Phenomena · Physics 2017-04-05 Andrei M. Bykov , Donald C. Ellison , Sergei M. Osipov

Astrophysical shocks are often studied in the high Mach number limit but weakly compressive fast shocks can occur in magnetic reconnection outflows and are considered to be a site of particle energization in solar flares. Here we study the…

Solar and Stellar Astrophysics · Physics 2012-06-26 Jaehong Park , Jared C. Workman , Eric G. Blackman , Chuang Ren , Robert Siller

Diffusive shock acceleration (DSA) at relativistic shocks is widely thought to be an important acceleration mechanism in various astrophysical jet sources, including radio-loud active galactic nuclei such as blazars. Such acceleration can…

High Energy Astrophysical Phenomena · Physics 2016-09-21 Matthew G. Baring , Markus Böttcher , Errol J. Summerlin

Diffusive shock acceleration (DSA) at relativistic shocks is expected to be an important acceleration mechanism in a variety of astrophysical objects including extragalactic jets in active galactic nuclei and gamma ray bursts. These sources…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Errol J. Summerlin , Matthew G. Baring

We study the suprathermal electron acceleration mechanism in a perpendicular magnetosonic shock wave in a high Mach number regime by using a particle-in-cell simulation. We find that shock surfing/surftron acceleration producing the…

Astrophysics · Physics 2009-11-07 M. Hoshino , N. Shimada

Plasma instabilities (e.g., Buneman, Weibel and other two-stream instabilities) excited in collisionless shocks are responsible for particle (electron, positron, and ion) acceleration. Using a new 3-D relativistic particle-in-cell code, we…

High Energy Astrophysical Phenomena · Physics 2011-02-11 K. -I. Nishikawa , J. Niemiec , P. E. Hardee , M. Medvedev , H. Sol , Y. Mizuno , B. Zhang , M. Pohl , M. Oka , D. H. Hartmann

Collisionless shocks are loosely defined as shocks where the transition between pre-and post-shock states happens on a length scale much shorter than the collisional mean free path. In the absence of collision to enforce thermal equilibrium…

Astrophysics of Galaxies · Physics 2015-06-16 Parviz Ghavamian , Steven J. Schwartz , Jeremy Mitchell , Adam Masters , J. Martin Laming

Diffusive shock acceleration (DSA), as an acceleration process for Galactic electrons at the solar wind termination shock (TS), is investigated with a comprehensive numerical model which incorporates shock-acceleration, particle drifts and…

Space Physics · Physics 2017-11-30 M. S. Potgieter , P. L. Prinsloo , R. D. Strauss

Collisionless shocks are pervasive in astrophysics and they are critical to understand cosmic ray acceleration. Laboratory experiments with intense lasers are now opening the way to explore and characterise the underlying microphysics,…

Plasma Physics · Physics 2014-01-14 A. Stockem , F. Fiuza , A. Bret , R. A. Fonseca , L. O. Silva

lasma instabilities excited in collisionless shocks are responsible for particle acceleration. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating…

High Energy Astrophysical Phenomena · Physics 2015-06-03 K. -I. Nishikawa , E. J. Choi , K. Min , P. Hardee , Y. Mizuno , B. Zhang , J. Niemiec , M. Medvedev , A. Nordlund , J. Fredriksen , M. Pohl , H. Sol , D. H. Hartmann , G. J. Fishman

Interplanetary Coronal Mass Ejection (ICME) shocks are known to accelerate particles and contribute significantly to Solar Energetic Particle (SEP) events. We have performed Magnetohydrodynamic-Particle in Cell (MHD-PIC) simulations of ICME…

Solar and Stellar Astrophysics · Physics 2021-12-22 Shanwlee Sow Mondal , Aveek Sarkar , Bhargav Vaidya , Andrea Mignone

Shocks in astrophysical fluids can generate suprathermal particles by first order (or diffusive) Fermi acceleration. In the test particle regime there is a simple relation between the spectrum of the accelerated particles and the jump…

Astrophysics · Physics 2009-11-06 Pasquale Blasi

We have performed 2D hybrid simulations of non-relativistic collisionless shocks in the presence of pre-existing energetic particles ("seeds"); such a study applies, for instance, to the re-acceleration of Galactic cosmic rays (CRs) in…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Damiano Caprioli , Horace Zhang , Anatoly Spitkovsky

We present a model for the creation of non-thermal particles via diffusive shock acceleration in a colliding-wind binary. Our model accounts for the oblique nature of the global shocks bounding the wind-wind collision region and the finite…

High Energy Astrophysical Phenomena · Physics 2021-04-28 J. M. Pittard , G. E. Romero , G. S. Vila

Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g.,Buneman, Weibel and other two-stream instabilities) created in collisionless shocks are responsible for particle…

Astrophysics · Physics 2009-11-10 K. -I. Nishikawa , P. Hardee , G. Richardson , R. Preece , H. Sol , G. J. Fishman

Particle acceleration is an ubiquitous phenomenon in astrophysical and space plasma. Diffusive shock acceleration (DSA) and stochastic turbulent acceleration are known to be the possible mechanisms for producing very high energetic…

High Energy Astrophysical Phenomena · Physics 2021-11-17 Sayan Kundu , Bhargav Vaidya , Andrea Mignone

Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are…

Astrophysics · Physics 2009-11-10 K. -I. Nishikawa , P. Hardee , G. Richardson , R. Preece , H. Sol , G. J. Fishman

Collisionless shocks occur in various fields of physics. In the context of space and astrophysics they have been investigated for many decades. However, a thorough understanding of shock formation and particle acceleration is still missing.…

Plasma Physics · Physics 2015-09-18 A. Stockem Novo , A. Bret , R. A. Fonseca , L. O. Silva

The problem of collisionless shocks is posed as the problem of understanding how in a completely collisionless streaming high-temperature plasma shocks can develop at all, forming discontinuous transition layers of thickness much less than…

Astrophysics · Physics 2008-05-15 R. A. Treumann , C. H. Jaroschek