TWO-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS OF THE NONRESONANT, COSMIC-RAY-DRIVEN INSTABILITY IN SUPERNOVA REMNANT SHOCKS

Yutaka Ohira*, Brian Reville, John G. Kirk, Fumio Takahara

*Corresponding author for this work

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

In supernova remnants, the nonlinear amplification of magnetic fields upstream of collisionless shocks is essential for the acceleration of cosmic rays to the energy of the "knee" at 10(15.5) eV. A nonresonant instability driven by the cosmic ray current is thought to be responsible for this effect. We perform two-dimensional, particle-in-cell simulations of this instability. We observe an initial growth of circularly polarized nonpropagating magnetic waves as predicted in linear theory. It is demonstrated that in some cases the magnetic energy density in the growing waves can grow to at least 10 times its initial value. We find no evidence of competing modes, nor of significant modification by thermal effects. At late times, we observe saturation of the instability in the simulation, but the mechanism responsible is an artifact of the periodic boundary conditions and has no counterpart in the supernova-shock scenario.

Original languageEnglish
Pages (from-to)445-450
Number of pages6
JournalAstrophysical Journal
Volume698
Issue number1
DOIs
Publication statusPublished - 10 Jun 2009

Keywords

  • ACCELERATION
  • TURBULENCE
  • shock waves
  • plasmas
  • supernova remnants
  • MAGNETIC-FIELD AMPLIFICATION
  • cosmic rays
  • MAXIMUM ENERGY
  • ALFVEN WAVES

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