2.5 dimensional time domain particle-in-cell simulation code for collection design

A 2.5-dimensional time-domain particle-in-cell simulation code for traveling-wave-tube collectors is presented. The code integrates various features of collector design, including depressed electrode configurations, external magnetic fields, and time-varying input electron distribution. This enables the user to change various tube parameters and observe the effect on collector efficiency nand thermal load. Among those parameters which are variable are depressed electrode voltages, geometry, magnetic field strength, and RF power. Numerical calculations have been made for two different types of collectors: a single-stage depressed collector which is used on the TMEC microtube, and a two-stage collector used on a 600-W Ku-band communication tube.<>