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particle acceleration, magnetic field generation and emission from relativistic jetsNonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), supernova remnants, 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 particle 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 spectral 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 of relativistic jets and try to make a connection with observations.
Document ID
20060047643
Document Type
Conference Paper
Authors
Nishikawa, K.-I.
(National Space Science and Technology Center Huntsville, AL, United States)
Hardee, P.
(Alabama Univ. Huntsville, AL, United States)
Hededal, C.
(Niels Bohr Inst. Copenhagen, Denmark)
Mizuno, Yosuke
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Fishman, G. Jerry
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Hartmann, D. H.
(Clemson Univ. SC, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Fluid Mechanics and Thermodynamics
Meeting Information
The Multi-Messenger Approach to High Energy Gamma-Ray Sources(Barcelona)
Distribution Limits
Public
Copyright
Other