New boundary conditions for 3D RF modelling

Summary form only given, as follows. Two new capabilities are being implemented into the 3-D particle-in-cell code ARGUS which will reduce substantially both problem size and computing time when modeling realistic geometries with high accuracies. In the time domain, a cylindrical radiative boundary condition will enable traveling-wave propagation to be simulated in accelerator structures. An application of interest is the input coupler in the SLAC X-band high-gradient structure where local field gradients and impedance matching are important issues. In the frequency domain. a quasi-periodic boundary condition will facilitate the cold-test analysis of 3-D periodic structures where many calculations are required to generate an ω-β diagram. Present applications include the crossed-field amplifier cavity and the cluster klystron cavity