Generation of microwave free-electron laser radiation using sheet electron beam and planar electromagnetic wiggler

An experimental study of sheet electron beam propagation through a planar electromagnetic wiggler and generation of microwave radiation by free-electron laser action has been carried out. The space charge dominated sheet electron beam of energy /spl sim/100-200 keV, current 50-150 A, and pulsewidth of 100-150 ns was propagated through a 20-period planar electromagnetic wiggler. Significant enhancement in the beam transmission through the wiggler was observed as the wiggler magnetic field was increased, even though the operating regime of the beam is space charge dominated. Generation of microwave radiation in E-band (60-90 GHz) was also observed when the sheet electron beam is injected through the niggler in the presence of wiggler magnetic field.