Time domain wake field computation with boundary element method

We describe and demonstrate a time-domain boundary-element method for numerical computation of wake fields. The accelerator structure is modeled with a surface mesh, and the wake field is easily split from the self fields of the source particles. The formulation for three-dimensional structures is introduced first, followed by two formulations for axisymmetric structures. We briefly describe methods for computing the wake potential in a boundary-element code. Finally, we compare the fully axisymmetric formulation with codes based on the finite integration technique (FIT). The other two formulations are demonstrated with modest examples.