Planar THz FELs Based on Intense Parallel Sheet Electron Beams and Intracavity Wave Scattering

Abstract

A design for a planar FEL operating in the terahertz frequency range at the multimegawatt power level is being jointly developed at the ELMI accelerator by the Budker Institute of Nuclear Physics and the Institute of Applied Physics. The FEL oscillator is driven by parallel intense sheet electron beams of moderately relativistic energy, and transitions to the above frequency range via a two-stage cascade scheme. The first beam generates a powerful millimeter pump wave, which then travels through special waveguides to the parallel channel and is scattered by the second beam into a wave of terahertz radiation. Various possible arrangements of the FEL scheme are discussed, and results from their simulation are presented. The results from cold tests of the FEL’s electrodynamic system are reported.