Magnetic Field Generation and Subsequent Field Dissipation with Plasma Heating in Relativistic Streaming Pair Plasmas

Abstract

Relativistic plasma streaming in background plasmas becomes unstable against the Weibel-type electromagnetic instability, which is one of effective mechanisms of magnetic field generation in cosmic plasmas. It is shown by using 3-D fully relativistic particle-in-cell (PIC) simulation code that magnetic fields perpendicular to the stream in an electron-positron (pair) plasma are generated in the early stage of the instability with small-scale sizes of the electron skin-depth. In the subsequent nonlinear stage there occurs magnetic reconnection which causes to make large-scale structure of magnetic fields in pair plasmas. The magnetic field dissipation through the magnetic reconnection leads to heating of the background plasma. These sequential physical processes are important for understanding of magnetic field generation in the relativistic shock of gamma-ray burst (GRB) sources in astrophysical plasmas.