Ko Noguchi

Intrinsic Radiation from Poynting Jets and Magnetized Collisionless Shocks

We summarize latest PIC simulation results on the radiation from Poynting jets and strongly magnetized collisionless shocks when a Poynting jet runs into cold ambient medium. We find that in all cases the radiative power output is much below that predicted by synchrotron radiation and the critical frequency is also much lower than the synchrotron critical frequency. We discuss the implications for the interpretation of GRB prompt emission data.

PIC Simulations of Prompt GRB Emissions

We review PIC simulation results of GRB emissions for both the Poynting flux and shock scenarios.

Self-consistent radiative effect on relativistic electromagnetic particle acceleration

We study the radiation damping effect on the relativistic acceleration of electron-positron plasmas with two-and-half–dimensional particle-incell(PIC) simulation. Particles are accelerated by Poynting flux via the diamagnetic relativistic pulse accelerator(DRPA), and decelerated by the self-consistently solved radiation damping force. With Ωce/ωpe ≥ 10, the Lorentz factor of the highest energy particles reaches γ > 100, and the acceleration still continues. The emitted radiation is peaked within few degrees from the direction of Poynting flux and strongly linearly polarized, which may be detectable in γ-ray burst(GRB) observations. We also show that the DRPA is insensitive to the initial supporting currents.