  Weibel instability created in collisionless shocks is responsible for
particle (electron, positron, and ion) acceleration. Using a 3-D relativistic
electromagnetic particle (REMP) code, we have investigated particle
acceleration associated with a relativistic electron-ion jet fronts propagating
into an ambient plasma without initial magnetic fields with a longer simulation
system in order to investigate nonlinear stage of the Weibel instability and
its acceleration mechanism. The current channels generated by the Weibel
instability induce the radial electric fields. The z component of the Poynting
vector (E x B) become positive in the large region along the jet propagation
direction. This leads to the acceleration of jet electrons along the jet. In
particular the E x B drift with the large scale current channel generated by
the ion Weibel instability accelerate electrons effectively in both parallel
and perpendicular directions.
