  We perform the numerical simulations of axisymmetric, relativistic, optically
thin jets under the influence of the radiation field of an accretion disk. We
show that starting from a very low injection velocity at the base, jets can be
accelerated to relativistic terminal speeds when traveling through the
radiation field. The jet gains momentum through the interaction with the
radiation field. We use a relativistic equation of state for multi-species
plasma, which self-consistently calculates the adiabatic index for the jet
material. All the jet solutions obtained are transonic in nature. In addition
to the acceleration of the jet to relativistic speeds, our results show that
the radiation field also acts as a collimating agent. The jets remain well
collimated under the effect of radiation pressure. We also show that if the jet
starts with a rotational velocity, the radiation field will reduce the angular
momentum of the jet beam.
