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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

The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless…

High Energy Astrophysical Phenomena · Physics 2016-07-27 A. Masters , A. H. Sulaiman , N. Sergis , L. Stawarz , M. Fujimoto , A. J. Coates , M. K. Dougherty

We perform a numerical-simulation study of the acceleration of electrons at shocks that propagate through a prespecified, kinematically defined turbulent magnetic field. The turbulence consists of broadband magnetic fluctuations that are…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Fan Guo , Joe Giacalone

Collisionless shock waves, found in supernova remnants, interstellar, stellar, and planetary environments, and laboratories, are one of nature's most powerful particle accelerators. This study combines in situ satellite measurements with…

High Energy Astrophysical Phenomena · Physics 2025-03-05 Savvas Raptis , Ahmad Lalti , Martin Lindberg , Drew L. Turner , Damiano Caprioli , James L. Burch

Plasma processes close to SNR shocks result in the amplification of magnetic fields and in the acceleration of electrons, injecting them into the diffusive acceleration mechanism. The acceleration of electrons and the B field amplification…

High Energy Astrophysical Phenomena · Physics 2015-06-09 M E Dieckmann , G Murphy , A Meli , L O C Drury

The formation of collisionless shock fronts is an ubiquitous phenomenon in space plasma environments. In the solar wind shocks might accompany coronal mass ejections, while even more violent events, such as supernovae, produce shock fronts…

High Energy Astrophysical Phenomena · Physics 2020-03-17 Cedric Schreiner , Patrick Kilian , Felix Spanier , Patricio A. Muñoz , Jörg Büchner

Collisionless shocks are efficient particle accelerators. At Earth, ions with energies exceeding 100 keV are seen upstream of the bow shock when the magnetic geometry is quasi-parallel, and large-scale supernova remnant shocks can…

High Energy Astrophysical Phenomena · Physics 2016-03-23 Torbjörn Sundberg , Christopher T. Haynes , David Burgess , Christian X. Mazelle

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

The early acceleration of protons and electrons in the nonrelativistic collisionless shocks with three obliquities are investigated through 1D particle-in-cell simulations. In the simulations, the charged particles possessing a velocity of…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Jun Fang , Chun-Yan Lu , Jing-Wen Yan , Huan Yu

We study the physics of electron acceleration at collisionless shocks that move through a plasma containing large-scale magnetic fluctuations. We numerically integrate the trajectories of a large number of electrons, which are treated as…

Solar and Stellar Astrophysics · Physics 2015-03-13 Fan Guo , Joe Giacalone

Shock accelerated electrons are found in many astrophysical environments, and the mechanisms by which they are accelerated to high energies are still not completely clear. For relatively high Mach numbers, the shock is supercritical, and…

Space Physics · Physics 2018-10-17 D. Trotta , D. Burgess

Cosmic rays and solar energetic particles may be accelerated to relativistic energies by shock waves in astrophysical plasmas. On the Sun, shocks and particle acceleration are often associated with the eruption of magnetized plasmoids,…

Solar and Stellar Astrophysics · Physics 2015-06-19 Eoin P. Carley , David M. Long , Jason P. Byrne , Pietro Zucca , D. Shaun Bloomfield , Joseph McCauley , Peter T. Gallagher

Shock waves propagating in collisionless heliospheric and astrophysical plasmas have been studied extensively over the decades. One prime motivation is to understand the nonthermal particle acceleration at shocks. Although the theory of…

High Energy Astrophysical Phenomena · Physics 2022-09-09 T. Amano , Y. Matsumoto , A. Bohdan , O. Kobzar , S. Matsukiyo , M. Oka , J. Niemiec , M. Pohl , M. Hoshino

Understanding the conditions conducive to particle acceleration at collisionless, non-relativistic shocks is important for the origin of cosmic rays. We use hybrid (kinetic ions -- fluid electrons) kinetic simulations to investigate…

High Energy Astrophysical Phenomena · Physics 2023-09-07 Luca Orusa , Damiano Caprioli

We use fully kinetic particle-in-cell simulations with unprecedentedly large transverse box sizes to study particle acceleration in weakly-magnetized mildly relativistic shocks traveling at a velocity $\approx 0.75c$ and a Mach number of…

High Energy Astrophysical Phenomena · Physics 2019-04-10 Patrick Crumley , Damiano Caprioli , Sera Markoff , Anatoly Spitkovsky

Electron acceleration mechanism at high Mach number collisionless shocks propagating in a weakly magnetized medium is investigated by a self-consistent two-dimensional particle-in-cell simulation. Simulation results show that strong…

Astrophysics · Physics 2008-12-18 Takanobu Amano , Masahiro Hoshino

In situ observations of energetic particles at the Earth's bow-shock that are attainable by the satellite missions have long created the opinion that electrons are most efficiently accelerated in a quasi-perpendicular shock geometry.…

High Energy Astrophysical Phenomena · Physics 2020-10-07 Adrian Hanusch , Tatyana Liseykina , Mikhail Malkov

Electron acceleration to non-thermal energies is known to occur in low Mach number (M<5) shocks in galaxy clusters and solar flares, but the electron acceleration mechanism remains poorly understood. Using two-dimensional (2D)…

High Energy Astrophysical Phenomena · Physics 2014-11-26 Xinyi Guo , Lorenzo Sironi , Ramesh Narayan

A full particle simulation study is carried out on the electron acceleration at a collisionless, relatively low Alfven Mach number (M_A=5), perpendicular shock. Recent self-consistent hybrid shock simulations have demonstrated that the…

Astrophysics · Physics 2011-02-11 Takayuki Umeda , Masahiro Yamao , Ryo Yamazaki

The process that allows cosmic rays to escape from their sources and be released into the Galaxy is still largely unknown. The comparison between cosmic-ray electron and proton spectra measured at Earth suggests that electrons are released…

High Energy Astrophysical Phenomena · Physics 2021-10-14 Giovanni Morlino , Silvia Celli
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