Phase variation in free-electron laser amplifiers

The evolution of the phase of the output radiation of free-electron laser amplifiers is investigated by means of a three-dimensional simulation code. The configuration employed consists of the propagation of a relativistic electron beam through a loss-free cylindrical waveguide in the presence of a helically symmetric wiggler and a uniform axial guide magnetic field. The analysis is fully three dimensional, and a set of model equations is discussed which describes the coupling between an ensemble of electrons and the radiation field of either the TE or TM modes. The model equations are solved numerically, and the output phase is studied with respect to variations in either frequency or electron beam energy. The output phase is found to depend sensitively on the wave frequency within the unstable bandwidth. In addition, the phase stability of the output radiation is discussed as a function of beam energy. Finally, the evolution of the phase for tapered wiggler free-electron lasers is studied.

[1]  Granatstein,et al.  Linear gain of a free-electron laser with an electromagnetic wiggler and an axial-guide magnetic field. , 1986, Physical review. A, General physics.

[2]  Ganguly,et al.  Nonlinear analysis of efficiency enhancement in free-electron-laser amplifiers. , 1986, Physical review. A, General physics.

[3]  Ganguly,et al.  Nonlinear analysis of free-electron-laser amplifiers in three dimensions. , 1985, Physical review. A, General physics.

[4]  H. Freund,et al.  Three-dimensional theory of the free-electron laser in the collective regime , 1983 .

[5]  H. Freund.  Nonlinear analysis of free-electron-laser amplifiers with axial guide fields , 1983 .

[6]  A. Fruchtman,et al.  Amplification on relativistic electron beams in combined helical and axial magnetic fields , 1982 .

[7]  H. Freund,et al.  Coherent and incoherent radiation from free-electron lasers with an axial guide field , 1981 .

[8]  I. Bernstein,et al.  Theory of the free-electron laser in combined helical pump and axial guide fields , 1981 .

[9]  L. Friedland.  Electron beam dynamics in combined guide and pump magnetic fields for free electron laser applications , 1980 .

[10]  H. Uhm,et al.  Theory of free electron laser instability in a relativistic annular electron beam. Technical report , 1980 .

[11]  J. Hirshfield,et al.  Free-electron laser with a strong axial magnetic field , 1980 .

[12]  T. Kwan,et al.  Investigation of the free electron laser with a guide magnetic field , 1979 .