3-D Finite-Element Analysis of TWT Grid Electron Guns

A novel three-dimensional FE procedure for the analysis of electron guns inside traveling wave tubes (TWTs) is presented, illustrating its main features. In this procedure, electron trajectories modeling cathode emission are obtained by solving a Vlasov-Poisson system of equations together with the relativistic dynamical equations of motion, under consistent particle injection conditions. This coupled electromechanical problem is solved iteratively by assuming stationary conditions. Simulation results concerning a gridded electron gun are presented, showing good agreement with available experimental data