Modelling of charged particle beams requires the solution of an electr
ostatic Poisson problem where the space charge density associated with
the beam can be determined by means of iterative procedures coupling
the field to the motion of the particles. The main critical points of
the procedure are: the coupling of field and motion equations and comp
utational burden of the whole process. A computer code for this purpos
e has been developed, different algorithms for the determination of sp
ace charge density and new techniques to speed up solution are present
ed and results discussed.