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

Abstract

The filamentation instability driven by two spatially uniform and counter-streaming beams of charged particles in plasmas is modelled by a particle-in-cell (PIC) simulation. Each beam consists of the electrons and positrons. The four species are equally dense and they 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 filamentation instability has saturated.

arXiv comment13 pages, 8 figures

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Cited by in corpus (6)

• Conditions for the onset of the current filamentation instability in the laboratory
• The filamentation instability driven by warm electron beams: Statistics and electric field generation
• One-dimensional particle simulation of the filamentation instability: electrostatic field driven by the magnetic pressure gradient force
• Hierarchy of instabilities for two counter-streaming magnetized pair beams
• Electric field generation by the electron beam filamentation instability: Filament size effects
• PIC simulation study of the interaction between a relativistically moving leptonic micro-cloud and ambient electrons