Possibility of using a large orbit regime for operation at bounce-frequency harmonics in a free-electron maser with a guiding magnetic field

It is suggested that a free-electron maser based on the LIU-3000 accelerato r (Joint Institute for Nuclear Research, Dubna) can be made to emit in the short-wavelength part of the microwave range by using radiation at harmonic s of the bounce frequency of an electron beam propagating along a helical t rajectory with a large gyration radius on the transverse inhomogeneity scal e of the rf field and selectively exciting a cylindrical waveguide mode who se azimuthal index is equal to the number of the harmonic. (C) 1999 America n Institute of Physics. [S1063-7850(99)00501-7].