LIAR- A NEW PROGRAM FOR THE MODELLING AND SIMULATION OF LINEAR ACCELERATORS WITH HIGH GRADIENTS AND SMALL EMITTANCES⁄

Linear accelerators are the central components of the proposed next generation of linear colliders. They need to provide acceler-ation of up to 750 GeV per beam while maintaining very small normalized emittances. Standard simulation programs, mainly developed for storage rings, do not meet the specific require-ments for high energy linear accelerators. We present a new pro-gram LIAR (”LInear Accelerator Research code”) that includes wakefield effects, a 4D coupled beam description, specific op-timization algorithms and other advanced features. Its modular structure allows to use and to extend it easily for different pur-poses. We present examples of simulations for SLC and NLC. The LIAR projec