WAVE-GUIDE STUDIES FOR FOM FEM

A 1 MW cw 200 GHz tunable efficient free electron maser is being desig ned at the FOM Institute for application in magnetic fusion research. In this paper several waveguide types are considered, including open w aveguides. Computer simulations of the amplification and guiding of th e mm wave in the undulator are reported. The simulation code is G3DH, written by E. Jerby, which solves a matrix dispersion relation. Gain v s frequency curves are shown. Efficiency calculations indicate that so me tapering is needed to reach the desired 1 MW mm wavepower. Simulati ons of a tapered undulator are presented by Caplan, and an overview of the FOM FEM is given by Urbanus et al. at this conference.