Computation of electromagnetic fields in multicell resonant structures for particle acceleration

The elecromagnetic fields in multicell resonant structures with cylindrical symmetry are computed by finite differences on a square mesh and point successive overrelaxation (PSOR). A careful discretization of the boundary conditions allows for an accurate calculation of the fields. All the resonant modes of the lowest TM01band-pass can be computed. Details of the numerical method, technical features of the program and results of computations in typical cases are reported.