RELATIONSHIP BETWEEN THE SPONTANEOUS AND THE STIMULATED RADIATIONS IN A NOVEL WIGGLER FREE-ELECTRON LASER

The spontaneous and the stimulated radiations, as well as the relationship between them, are calculated for an electron moving in the wiggler with the independent magnetostatic-field on the axial (z) coordinates. It is shown that the Madey's law is still valid in the novel wiggler case. The small signal gain of free-clectron laser is calculated in a novel wiggler.