Simulation study of the filamentation of counter-streaming beams of the electrons and positrons in plasmas

Dieckmann, M.E. and Shukla, P.K. and Stenflo, L. (2009) Simulation study of the filamentation of counter-streaming beams of the electrons and positrons in plasmas. Plasma Physics and Controlled Fusion, 51 (6). 065015. ISSN 0741-3335 (http://dx.doi.org/10.1088/0741-3335/51/6/065015)

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Abstract

The filamentation instability (FI) driven by two spatially uniform and counter-streaming beams of charged particles in plasmas is modelled by a particle-in-cell simulation. Each beam consists of electrons and positrons. The four species are equally dense and have the same temperature. The one-dimensional simulation direction is orthogonal to the beam velocity vector. The magnetic field grows spontaneously and rearranges the particles in space, such that the distributions of the electrons of one beam and the positrons of the second beam match. The simulation demonstrates that as a result no electrostatic field is generated by the magnetic field through its magnetic pressure gradient prior to its saturation. This electrostatic field would be repulsive at the centres of the filaments and limit the maximum charge and current density. The filaments of electrons and positrons in this simulation reach higher charge and current densities than in one with no positrons. The oscillations of the magnetic field strength induced by the magnetically trapped particles result in an oscillatory magnetic pressure gradient force. The latter interplays with the statistical fluctuations in the particle density and it probably enforces a charge separation, by which electrostatic waves grow after the FI has saturated.

  • Item type:Article
    ID code:19139
    Dates:
    Date
    Event
    June 2009
    Published
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Strathprints Administrator
    Date deposited:21 May 2010 09:34
    Last modified:08 Apr 2024 17:52
    URI:https://strathprints.strath.ac.uk/id/eprint/19139
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