THE GENERAL PARTICLE TRACER CODE

Abstract The 3D General Particle Tracer (GPT) code has been extended,to perform ,multi-frequency multi-pass free- electron laser (FEL) simulations. The new model is based onaxisymmetric,multiple Gaussian waves propagating in free space, without averaging over the undulator period. The field equations are integrated simultaneously with the equations of motion of the particles, making the model ideally suited to calculate electron ,beam ,phase-space distributions during and after FEL interaction. Due to the from-first-principles approach of the model, it is useful to avariety of radiation problems. The model ,and a proof- of-principle test are presented.