Magnetic field generation and subsequent field dissipation with plasma heating in relativistic streaming pair plasmas

Relativistic plasma streaming in background plasmas becomes unstable agains t the Weibel-type electromagnetic instability, which is one of effective me chanisms of magnetic field generation in cosmic plasmas. It is shown by usi ng 3-D fully relativistic particle-in-cell (PIC) simulation code that magne tic fields perpendicular to the stream in an electron-positron (pair) plasm a are generated in the early stage of the instability with small-scale size s of the electron skin-depth. In the subsequent nonlinear stage there occur s magnetic reconnection which causes to make large-scale structure of magne tic fields in pair plasmas. The magnetic field dissipation through the magn etic reconnection leads to heating of the background plasma. These sequenti al physical processes are important for understanding of magnetic field gen eration in the relativistic shock of gamma-ray burst (GRB) sources in astro physical plasmas.