One-dimensional particle simulation of the filamentation instability: electrostatic field driven by the magnetic pressure gradient force

M. E. Dieckmann; I. Kourakis; M. Borghesi; G. Rowlands

doi:10.1063/1.3160629

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arXiv · 0906.1878

One-dimensional particle simulation of the filamentation instability: electrostatic field driven by the magnetic pressure gradient force

M. E. Dieckmann·I. Kourakis·M. Borghesi·G. Rowlands

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Abstract

Two counter-propagating cool and equally dense electron beams are modelled with particle-in-cell (PIC) simulations. The electron beam filamentation instability is examined in one spatial dimension, which is an approximation for a quasi-planar filament boundary. It is confirmed, that the force on the electrons imposed by the electrostatic field, which develops during the nonlinear stage of the instability, oscillates around a mean value that equals the magnetic pressure gradient force. The forces acting on the electrons due to the electrostatic and the magnetic field have a similar strength. The electrostatic field reduces the confining force close to the stable equilibrium of each filament and increases it farther away, limiting the peak density. The confining time-averaged total potential permits an overlap of current filaments with an opposite flow direction.

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M. E. Dieckmann, I. Kourakis, M. Borghesi, G. Rowlands. 2009-06-10. One-dimensional particle simulation of the filamentation instability: electrostatic field driven by the magnetic pressure gradient force. https://doi.org/10.1063/1.3160629

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