Progress on a 3D particle-in-cell model of a W-band klystron

Summary form only given. For a significant class of microwave-beam devices, including multibeam tubes and devices with azimuthally asymmetric interaction circuits, two-dimensional models do not provide a description of the key physical phenomena. A fully three-dimensional computational model which captures the kinetic and nonlinear aspects of such devices is required. XOOPIC is in the process of being extended from a 2d electromagnetic PIC code into a 3d parallel code. The 3d code will be applied to modelling a klystron operating in the W-band. The XOOPIC code is presently a 2d particle-in-cell code in r-z and x-y coordinates written in C++. XOOPIC presently runs on Unix platforms ranging from Linux PCs to workstations to MPI-capable parallel computers. Design and initial implementation of an extension from two to three dimensions is described for the XOOPIC code. The code will be applied to a high power klystron.