Preliminary simulation of FEA electron gun for RF application

FEA has some advantages over existing thermionic cathode, e.g. large current density, instant turn-on, room-temperature operation, etc, so several RF devices experiments using FEA have been reported, including TWTs and prebunched Klystrode. Some simulation of FEA electron gun has been carried out, considering different focusing electrodes' structure, anode potential, even the roles of either a fixed magnetostatic field values or the leakage magnetic field from PPM focusing in the cathode area. Initial condition of field emission electrons being considered, this paper gives some simulation results for different focusing electrodes and magnetostatic field.