27-31 August 2018
LVH, Luisenstraße 58, 10117 Berlin
Europe/Berlin timezone
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Contribution Poster (A0 portrait)

LVH, Luisenstraße 58, 10117 Berlin -

Fermi particle acceleration in trans-relativistic shocks with magnetic field amplification


  • Prof. Don ELLISON

Primary authors


Abstract content

First-order Fermi particle acceleration in supernova remnant (SNR) shocks is generally considered as the most likely production mechanism for the bulk of the cosmic rays (CRs), i.e., those with energies below the knee at $\sim 10^{15}$ eV. The SNR origin of higher energy CRs remains uncertain since the shock speeds of typical SNRs are too small to produce CRs above $\sim 10^{16}$ eV in the time and space limits of the expanding blast wave. Recently, however, a class of relativistic supernovae has been discovered having trans-relativistic ejecta speeds. Fermi acceleration in trans-relativistic shocks differs importantly from that in either non-relativistic or ultra-relativistic shocks and may allow CR production to energies well above the knee. A fundamental aspect of efficient Fermi acceleration in all shocks is the production of magnetic turbulence in the shock precursor by back streaming CRs. We have recently included a largely self-consistent calculation of magnetic field amplification (MFA) in a nonlinear Monte Carlo simulation of trans-relativistic shocks including the resonant streaming instability and two non-resonant instabilities: the short-wavelength Bell instability and the long-wavelength current-driven instability. We will describe initial results from this work.