Saturation Mechanisms of Magnetic Field Growth in a Two-Stream Mediated Weibel Instability

We present 2X2V continuum Vlasov-Maxwell simulations of colliding electron populations to study the non-linear saturation of magnetic field growth resulting from competition between Two-Stream, Oblique, and Weibel modes in non-relativistic and weakly relativistic regimes. Understanding the robustness of the Wiebel instability to other modes present is important for estimating its role in generating magnetic fields in many astrophysical scenarios with interpenetrating plasma flows. In the isotropic temperature case, we find that for hotter temperatures non-linear saturation leads to magnetic fields with 1e-2 to 1e-1 of the equipartition energy density. However, for colder temperatures the non-linear state of the Weibel instability is significantly disturbed and results in energy conversion efficiencies much lower than 1e-2, an effect not observed in 1X2V simulations. Simulations of non-relativistic counter streaming velocities with large initial anisotropic temperatures relevant to cosmological scenarios are also presented.