Effect of Background Magnetic Field on Ion Weibel Instability With High‐Intensity Short‐Pulse Lasers

ABSTRACT The effect of finite background magnetic field on magnetic field amplification by Weibel instability using high‐intensity short‐pulse lasers is investigated. We consider Weibel instability for counter‐streaming sub‐relativistic plasma flows generated by shooting pure carbon targets with short‐pulse lasers. Using 2D and 3D particle‐in‐cell simulations, we show that a beam perpendicular background magnetic field, which magnetizes the electrons, can enhance the growth of the Weibel magnetic field, which is consistent with previous theories and simulations for weakly magnetized astrophysical shocks. The results indicate that magnetic field can be generated with this setup.