NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Simulation Study of Magnetic Fields generated by the Electromagnetic Filamentation Instability driven by Pair LoadingUsing a 3-D relativistic particle-in-cell (RPIC) code, we have investigated particle acceleration associated with a relativistic electron-positron (cold) jet propagating into ambient electron-positron and electron-ion plasmas without initial magnetic fields in order to investigate the nonlinear stage of the Weibel instability. We have also performed simulations with broad Lorentz factor distribution of jet electrons and positrons, which are assumed to be created by the photon annihilation. The growth time and nonlinear saturation levels depend on the initial jet parallel velocity distributions and ambient plasma. Simulations show that the Weibel instability created in the collisionless shocks accelerates jet and ambient particles both perpendicular and parallel to the jet propagation direction. The nonlinear fluctuation amplitude of densities, currents, electric, and magnetic fields in the electron-ion ambient plasma are larger than those in the electron-positron ambient plasma. We have shown that plasma instabilities driven by these streaming electron-positron pairs are responsible for the excitation of near-equipartition, turbulent magnetic fields. These fields maintain a strong saturated level on timescales much longer than the electron skin depth at least for the duration of the simulations. Our results reveal the importance of the electromagnetic filamentation instability in ensuring an effective coupling between electron-positron pairs and ions, and may help explain the origin of large upstream fields in GRB shock.
Document ID
20070018776
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Nishikawa, K.-I.
(National Space Science and Technology Center Huntsville, AL, United States)
Ramirez-Ruiz, E.
(California Univ. Santa Cruz, CA, United States)
Hededal, C.
(Niels Bohr Inst. Copenhagen, Denmark)
Hardee, P.
(Alabama Univ. Tuscaloosa, AL, United States)
Mizuno, Y.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Fishman, G. J.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2007
Subject Category
Astrophysics
Meeting Information
Meeting: THe Next Decade of Gamma-ray Bursts Afterglows
Location: Amsterdam
Country: Netherlands
Start Date: March 19, 2007
End Date: March 23, 2007
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available