TESLA: effective simulation code for vacuum electronic devices with external cavities

Summary form only given, as follows. TESLA (Telegraphist´s Equations Solution for Linear Beam Amplifiers) is a new code designed to simulate linear beam vacuum electronic devices with external cavities, such as klystrons, extended interaction klystrons, twistrons, and coupled cavity amplifiers. The model includes a self-consistent, nonlinear solution of the three-dimensional electron equations of motion and the solution of time-dependent field equations. The model differs from the conventional Particle in Cell approach in that the field spectrum is assumed to consist of a carrier frequency and its harmonics with slow varying envelopes. Also, fields in the external cavities are modeled with circuit like equations and couple to fields in the beam region through boundary conditions on the beam tunnel wall The model in TESLA is an extension of the model used in our gyrotron code MAGY. The code TESLA has been verified by comparison with MAGIC calculations and validated by comparison with measured data. The TESLA code predicts the same results as MAGIC code for a simple two cavity klystron design while the computational time for TESLA is factor 10/sup 3/ less than for MAGIC 2D. Thus, TESLA is highly efficient code suitable for running on desktop computers with standard configurations The TESLA algorithm is currently being modified to simulate multiple beam klystrons on multiprocessor machines.