COCA: A novel 3-D FE simulator for the design of TWTs multistage collectors

In this paper, the simulator COCA, a novel fully three-dimensional (3-D) fi nite-element (FE) tool for the design of multistage depressed TWTs collecto rs is illustrated. COCA has been developed at the University of Catania und er an ESA/ESTEC project. The complete simulator consists of three main modu les: a fully 3-D deterministic/neural FE mesh generator, an FE Vlasov solve r coupled with an electron trajectory tracer taking into account also exter nal magnetic fields, and a postprocessing module for result restitution, in cluding secondary electron emission effects. All the functions are interact ively managed and executed by means of an especially developed user-friendl y graphical user interface which controls all the various aspects of a simu lation session. The results of a simulation test pet-formed on an asymmetri c collector are also reported showing excellent agreement with available me asured data. The COCA simulator provides the user with flexible and effecti ve tools to design, test, optimize, and verify innovative asymmetrical geom etries for TWT collectors.