Prediction of the FOM FEM experimental results using multi-mode time-dependent simulations

The Free Electron Maser (FEM) constructed at the FOM Institute, Netherlands is now ready to undergo the first set of short pulse (< 20 mu s) experiments to demonstrate the capability of generating 1 MW of microwave power in the range 130-250 GHz. Predictions of the FEM performance requires a time-dependent multi-frequency simulation code which can include the detailed frequency dependence of the measured microwave transmission and feedback system, the time-dependent voltage pulse and the initial shot noise in the electron beam. Simulations predict that in spite of imperfections in the microwave circuit, transmission losses and a substantial voltage droop of 0.34% per mu s, megawatt levels of microwave power will be generated and observed within the 10-20 mu s voltage pulse. (C) 1998 Elsevier Science B.V. All rights reserved.