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Particle Acceleration and Emission in Relativistic JetsShock wave acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. While some Fermi acceleration may occur at the jet front, the majority of electron acceleration takes place behind the jet front and cannot be characterized as Fermi acceleration. The simulation results show that this instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields, which 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.
Document ID
20030069050
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Nishikawa, K.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Hardee, P. E.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Richardson, G. A.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Preece, R. D.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Sol, H.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Fishman, G. J.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Astrophysics
Meeting Information
Meeting: Partucle Acceleration in Astrophysical Objects
Location: Cracow
Country: Poland
Start Date: June 24, 2003
End Date: June 28, 2003
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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