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Record 30 of 152
Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets
Author and Affiliation:
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)
Abstract: Nonthermal 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.
Publication Date: Jan 01, 2006
Document ID:
20060047643
(Acquired Oct 06, 2006)
Subject Category: FLUID MECHANICS AND THERMODYNAMICS
Document Type: Conference Paper
Meeting Information: The Multi-Messenger Approach to High Energy Gamma-Ray Sources; 4-7 Jul. 2006; Barcelona; Spain
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: Copyright
NASA Terms: EMISSION SPECTRA; MAGNETIC FIELDS; PARTICLE ACCELERATION; RELATIVISTIC EFFECTS; JET FLOW; SIMULATION; DEFLECTION; PLASMA WAVES; POSITRONS; SUPERNOVA REMNANTS; WEIBEL INSTABILITY; ELECTRONS; NONTHERMAL RADIATION
Availability Source: Other Sources
Availability Notes: Abstract Only
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