Particle Acceleration, Magnetic Field Generation, and Associated Emission in Collisionless Relativistic Jets

Abstract

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that acceleration occurs within the downstream jet. Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The ``jitter'' radiation from deflected electrons has different properties than synchrotron radiation which assumes a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

4 pages, 3 figures, contributed talk at the workshop: High Energy Phenomena in Relativistic Outflows (HEPRO), Dublin, 24-28 September 2007. Fig. 3 is replaced by the correct version

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Cited by in corpus (6)

• Apar-T: code, validation, and physical interpretation of particle-in-cell results
• PIC methods in astrophysics: Simulations of relativistic jets and kinetic physics in astrophysical systems
• Evolution of Global Relativistic Jets: Collimations and Expansion with kKHI and the Weibel Instability
• Radiation from sub-Larmor scale magnetic fields
• Magnetic Field Generation in Core-Sheath Jets via the Kinetic Kelvin-Helmholtz Instability
• Magnetic field generation in a jet-sheath plasma via the kinetic Kelvin-Helmholtz instability