Particle acceleration, magnetic field generation, and emission in relativistic pair jets

Nishikawa, K.-I. and Hardee, P. and Hededal, C. B. and Richardson, G. and Sol, H. and Preece, R. and Fishman, G. J. (2005) Particle acceleration, magnetic field generation, and emission in relativistic pair jets. Il nuovo cimento C, 28 (3). pp. 435-438. ISSN 1826-9885

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Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., Buneman, Weibel and other two-stream instabilities) created in collisionless 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 into an ambient plasma. We find that the growth times of Weibel instability are proportional to the Lorentz factors of jets. Simulations show that the Weibel instability created in the collisionless shock front accelerates jet and ambient particles both perpendicular and parallel to the jet propagation direction. The small-scale magnetic field structure generated by the Weibel instability is appropriate to the generation of “jitter” radiation from deflected electrons (positrons) as opposed to synchrotron radiation. The jitter radiation resulting from small scale magnetic field structures may be important for understanding the complex time structure and spectral evolution observed in gamma-ray bursts or other astrophysical sources containing relativistic jets and relativistic collisionless shocks.

Item Type: Article
Additional Information: Paper presented at the “4th Workshop on Gamma-Ray Burst in the Afterglow Era”, Rome, October 18-22, 2004.
Uncontrolled Keywords: Active and peculiar galaxies and related systems ; Jets and bursts; galactic winds and fountains ; X-ray sources; X-ray bursts ; γ-ray sources; γ-ray bursts
Subjects: 500 Scienze naturali e Matematica > 530 Fisica
Depositing User: Marina Spanti
Date Deposited: 16 Mar 2020 10:55
Last Modified: 16 Mar 2020 10:55

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