The transport of cosmic rays in self-excited magnetic turbulence

B. Reville*, S. O'Sullivan, P. Duffy, J. G. Kirk

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

70 Citations (Scopus)

Abstract

The process of diffusive shock acceleration relies on the efficacy with which hydromagnetic waves can scatter charged particles in the precursor of a shock. The growth of self-generated waves is driven by both resonant and non-resonant processes. We perform high-resolution magnetohydrodynamic simulations of the non-resonant cosmic ray driven instability, in which the unstable waves are excited beyond the linear regime. In a snapshot of the resultant field, particle transport simulations are carried out. The use of a static snapshot of the field is reasonable given that the Larmor period for particles is typically very short relative to the instability growth time. The diffusion rate is found to be close to, or below, the Bohm limit for a range of energies. This provides the first explicit demonstration that self-excited turbulence reduces the diffusion coefficient and has important implications for cosmic-ray transport and acceleration in supernova remnants.

Original languageEnglish
Pages (from-to)509-515
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Volume386
Issue number1
DOIs
Publication statusPublished - 01 May 2008

Keywords

  • PARTICLE-ACCELERATION
  • turbulence
  • MHD
  • SHOCK ACCELERATION
  • ALFVEN WAVES
  • MAGNETOHYDRODYNAMICS
  • FIELD
  • acceleration of particles
  • ENERGY
  • cosmic rays
  • NONLINEAR AMPLIFICATION
  • instabilities
  • CURRENT-DRIVEN INSTABILITY

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