Generation of external laser field harmonics by an electron beam in a multicomponent undulator with an axial field

An analysis is made of a frequency converter system for coherent radiation using an electron beam propagating through a two-component undulator. It is shown that in many cases, the introduction (in addition to the fields of two helical undulators) of a strong axial magnetic field can substantially improve the gain and intensity of the generated wave. The gain is calculated allowing for the energy scatter of the beam electrons.