Density filamentation nonlinearly driven by the Weibel instability in relativistic beam plasmas

Density filamentation has been observed in many beam-plasma simulations and experiments. Because current is a pure transverse mode, charge density cannot be produced directly by the process. To explain this phenomenon, several mechanisms are proposed such as coupling of Weibel instability to two-stream instability, Langmuir wave, differences thermal velocities between beam return currents, magnetic pressure gradient force, etc. In paper, it shown that Lorentz factor can, fact, represent nonlinear behavior plasma fluid further nonuniform distribution can give rise electrostatic fields filaments. Simulation results together with theoretical analyses presented.