FRONTIERS IN COMPUTATIONAL ASTROPHYSICS

Particle and Flames in Radiative and Magnetic Flows

October 11-15, 2010
Lyon, France

Contribution of Ken-Ichi Nishikawa

Title

Simulation of relativistic shocks and associated radiation from turbulent magnetic fields

Topics

"Explosive fate of stars"

Keywords

relativistic jet, Weibel instaility, magentic field generation, radiatiion

Abstract

Recent PIC simulations of relativistic electron- positron (electron- ion) jets injected into a stationary medium show that particle acceleration occurs at shocked regions. Simulations show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields and particle acceleration. These magnetic fields contribute to the electron's transverse deflection behind the shock. The ``jitter'' radiation from deflected electrons in turbulent magnetic fields has different properties than synchrotron radiation, which is calculated in a uniform magnetic field. This jitter radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants. We will present detailed spectra for conditions relevant for various astrophysical sites of shock formation via the Weibel instability. In particular we will discuss the application to GRBs and SNRs.

Talk