Magnetic Field Generation and Particle Energization at Relativistic Shear Boundaries in Collisionless Electron-Positron Plasmas

Abstract

Using 2.5-dimensional Particle-in-Cell simulations, we study the kinetic physics of relativistic shear flow boundary in collisionless electron-positron (e+e-) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary, driven by streaming instabilities across the shear interface and sustained by the shear flow. Nonthermal, anisotropic high-energy particles are accelerated across field lines to produce a power-law tail, truncated at energies below the shear Lorentz factor. These results have important implications for the dissipation and radiation of jets in blazars, gamma-ray bursts and other relativistic outflows.Comment: 16 pages 5 figures. revised 1/28/2013. submitted to APJ