A current-driven instability in parallel, relativistic shocks

B. Reville*, J. G. Kirk, P. Duffy

*Corresponding author for this work

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Recently, Bell ( 2004 Mon. Not. R. Astron. Soc. 353 550) has reanalysed the problem of wave excitation by cosmic rays propagating in the pre-cursor region of a supernova remnant shock front. He pointed out a strong, non-resonant, current-driven instability that had been overlooked in the kinetic treatments by Achterberg ( 1983 Astron. Astrophys. 119 274) and McKenzie and Volk ( 1982 Astron. Astrophys. 116 191), and suggested that it is responsible for substantial amplification of the ambient magnetic field. Magnetic field amplification is also an important issue in the problem of the formation and structure of relativistic shock fronts, particularly in relation to models of gamma-ray bursts. We have therefore generalized the linear analysis to apply to this case, assuming a relativistic background plasma and a monoenergetic, unidirectional incoming proton beam. We find essentially the same non-resonant instability observed by Bell and show that also, under GRB conditions, it grows much faster than the resonant waves. We quantify the extent to which thermal effects in the background plasma limit the maximum growth rate.

Original languageEnglish
Pages (from-to)1741-1747
Number of pages7
JournalPlasma Physics and Controlled Fusion
Volume48
Issue number12
DOIs
Publication statusPublished - Dec 2006

Keywords

  • WEIBEL INSTABILITY
  • GAMMA-RAY BURSTS
  • MAGNETIC-FIELD GENERATION
  • AMPLIFICATION
  • COSMIC-RAYS
  • PARTICLE-ACCELERATION
  • WAVES
  • ENERGY
  • PLASMA
  • PHYSICS

Cite this