Influence of beam temperature and plasma collisions on the Weibel instability

Weibel (filamentation) instability is important for the fast ignition (FI) scheme, beam transport in accelerators and astrophysical scenario. We present 2D and 3D particle-in- cell (PIC) simulations of the Weibel instability including beam temperature and ambient plasma collisions. Our simulation results show that instability disappears when transverse beam temperature T_perp/mc² > n_b/n₀, where n_b and n₀ are beam and background plasma densities. We show that background plasma collisions in the return current revive back the Weibel instability even in presence of high beam temperature. An analytical model, which predicts the similar results, has also been developed. Furthermore, some extensive simulations of longitudinal 2D simulation geometry can also be reported to understand the coupled Weibel and two-stream instabilities.