Journal
ASTROPHYSICAL JOURNAL
Volume 671, Issue 2, Pages 1877-1885Publisher
UNIV CHICAGO PRESS
DOI: 10.1086/522072
Keywords
gamma rays : bursts; instabilities; magnetic fields; plasmas; shock waves
Categories
Ask authors/readers for more resources
We investigate here the effects of plasma instabilities driven by rapid e(+/-) -pair cascades, which arise in the environment of gamma-ray burst (GRB) sources as a result of back-scattering of a seed fraction of the original spectrum. The injection of e(+/-) pairs induces strong streaming motions in the ambient medium. One therefore expects the pair-enriched medium ahead of the forward shock to be strongly sheared on length scales comparable to the radiation front thickness. Using three-dimensional particle-in-cell simulations, we show that plasma instabilities driven by these streaming e(+/-) pairs are responsible for the excitation of near-equipartition, turbulent magnetic fields. Our results reveal the importance of the electromagnetic filamentation instability in ensuring an effective coupling between e(+/-) pairs and ions, and may help explain the origin of large upstream fields in GRB shocks.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available