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Record 42 of 272
Particle Acceleration and Radiation associated with Magnetic Field Generation from Relativistic Collisionless Shocks
Author and Affiliation:
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)
Abstract: Shock 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.
Publication Date: Jan 01, 2003
Document ID:
20030106444
(Acquired Nov 04, 2003)
Subject Category: NUCLEAR PHYSICS
Document Type: Preprint
Meeting Information: Gamma Ray Burst Symposium; 8-12 Sep. 2003; Santa Fe, NM; United States
Financial Sponsor: NASA Marshall Space Flight Center; Huntsville, AL, United States
Organization Source: NASA Marshall Space Flight Center; Huntsville, AL, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: DATA BASES; ACCELERATION (PHYSICS); SHOCK WAVES; PARTICLE ACCELERATION; ASTROPHYSICS; PLASMA WAVES; THREE DIMENSIONAL MODELS; MAGNETIC FIELDS
Availability Source: Other Sources
Availability Notes: Abstract Only
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