Vi. Kurilko et Vv. Ognivenko, DYNAMICS OF A MONOENERGETIC POINT-LIKE ELECTRON FLOW IN A HELIX UNDULATOR, Plasma physics reports, 20(7), 1994, pp. 568-573
A self-consistent linear theory is developed to describe the motion of
a monoenergetic nondivergent point charge flow in a helix undulator w
here the resultant undulator radiation field is taken into account. On
this basis, a boundary in the space of external parameters for the co
nsidered nonequilibrium system (beam + undulator) is established that
separates the modes of its operation as a source of stimulated radiati
on (free electron laser) and of incoherent spontaneous radiation (conv
entional source of undulator radiation). Physical mechanisms responsib
le for transitions from one mode to another under the corresponding pa
rameter changes are discussed.