Simulation Codes for High Brightness Electron Beam Experiments

The high brightness required by a short wavelength SASE FEL may be reached only with an accurate design of the electron beam dynamics from the generation in the rf-injector up to the undulator. The beam dynamics is affected by strong self consistent effects at injection, in the compression stage and during the FEL process. The support of numerical simulations is extensively used in the predictions of the beam behaviour in these non linear dynamical conditions. We present a review of available simulation tools, currently exploited in the design of a short wavelength free electron laser.