Relativistic klystron wakefields

Monopole, dipole, and quadrupole wake potentials are calculated for two cavities in a standing-wave relativistic klystron, using two independent programs, TBCI and AMOS. The results of TBCI and AMOS agree very well for a variety of test cases. However, for wakes with frequencies above cutoff, both problems calculated spurious reflections from the open boundaries of the beam pipe. These can be eliminated using long pipes, but at the expense of long computer run time. It was demonstrated that a significant part of the spurious reflections at the open ends can be mitigated by using lossy dielectrics with finite conductivities at the open ends of the beam pipe to absorb the outgoing waves