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3-D RPIC simulations of relativistic jets: Particle acceleration, magnetic field generation, and emissionNonthermal radiation observed from astrophysical systems containing (relativistic) jets and shocks, e.g., supernova remnants, active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that acceleration occurs within the downstream jet, rather than by the scattering of particles back and forth across the shock as in Fermi acceleration. 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 is calculated in 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. We will review recent PIC simulations which show particle acceleration in jets.
Document ID
20060013647
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Nishikawa, K.-I.
(National Space Science and Technology Center Huntsville, AL, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Astrophysics
Meeting Information
Meeting: 6th International Conference on High Energy Laboratory of Astrophysics
Location: Houston, TX
Country: United States
Start Date: March 11, 2006
End Date: March 14, 2006
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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