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Title: Coherent-state description of free-electron lasers

Technical Report ·
OSTI ID:5474876
 [1]
  1. Alabama A and M Univ., Normal, AL (United States)

It is generally accepted that the overall performance of free- electron lasers (FEL) can be understood without quantum mechanics. However, there are features of FEL such as photon statistics which can only be described quantum-mechanically. Although the majority of quantum-mechanical studies of FEL are devoted to one-particle models; there are also many studies on are so complicated that it is not easy to follow the developments with a clearer picture in mind. The origin of the problem is the quantum recoils of the electrons. So in the present study, we try to gain a clearer picture of the many-body effects by making the recoilless approximation. A simple model of FEL consists of a beam of relativistic electrons propagating through a spatially periodic magnetostatic wiggler field. The resulting laser output is propagating along the same direction as that of the electron beam. Quantum-mechanical analysis of FEL are usually based on the Bambini-Renieri frame which moves in the same direction as the propagating laser beam with a relativistic speed so that the wiggler field appears almost as a plane-wave radiation, the frequency of the wiggler field coincides with that of the laser, and the electron motion is nonrelativistic. Although in reality the laser beam can only derive its energy at the expense of the kinetic energy of the electrons, it appears in the Bambini-Renieri frame as if the photons of the laser were scattered from the fictitious photons of the wiggler field by the electrons.

Research Organization:
Lawrence Livermore National Lab., CA (United States); Alabama A and M Univ., Normal, AL (United States)
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
5474876
Report Number(s):
UCRL-CR-103758-SUP; ON: DE91017077
Country of Publication:
United States
Language:
English