The AMOS (Azimuthal MOde Simulator) wakefield code

AMOS (Azimuthal MOde Simulator) is an electromagnetic simulation computer program that has been developed to study and design accelerator cavities. AMOS simulates the temporal evolution of fields in rotationally symmetric volumes, using a harmonic expansion in the azimuthal coordinate ({phi}) to project the fields onto a two-dimensional, r {minus} z, finite-difference grid. An interactive preprocessor has been developed which allows the user to easily construct AMOS grids from geometric models. A wakefield postprocessor has also been developed to compute wake potentials and impedances from AMOS time-domain data. Graphical postprocessing software is presently under development. AMOS has been used to study accelerating modules in several linear accelerators, including the Advanced Test Accelerator (ATA), the Experimental Test Accelerator-II (ETA-II), SNOMAD, Dual Access Radiographic Hydrodynamics Test facility (DARHT), and others. Ongoing AMOS development objectives include the installation of an open'' boundary condition (Lindman), an rf tensor ferrite model, and the extension of AMOS to irregular, boundary conforming grids. 9 refs., 10 figs., 1 tab.