title: Particle simulation of an ultrarelativistic two-stream instability.
abstract: A two-stream instability in an unmagnetized plasma is examined by a particle-in-cell simulation. Each beam initially consists of cold electrons and protons that stream at a relative Lorentz factor 100. This is representative for plasma close to the external shocks of gamma-ray bursts. An electrostatic wave develops which saturates by trapping electrons. This wave collapses and the resulting electrostatic turbulence gives an electron momentum distribution that resembles a power law with a spectral break. Some electrons reach Lorentz factors over 1000.
authors.affiliation: Department of Theoretical Space and Astrophysics, Ruhr-University Bochum, 44780 Bochum, Germany.
authors.forename: M E
authors.initials: ME
authors.lastname: Dieckmann