Analysis and optimization of a freeelectron laser with an irregular waveguide
Abstract
Using a timedependent approach, the analysis and optimization of a planar freeelectron laser (FEL) amplifier with an axial magnetic field and an irregular waveguide is performed. By applying methods of nonlinear dynamics, a selfconsistent reduced model of the FEL is built in a special phase space. This reduced model is the generalization of the ColsonBonifacio model and takes into account the intricate dynamics of electrons in the pump magnetic field and the intramode scattering in the irregular waveguide. The reduced model and concepts of evolutionary computation are used to find optimal waveguide profiles. The numerical simulation of the original nonsimplified model is performed to check the effectiveness of found optimal profiles. To demonstrate advantages of the proposed FEL configuration, the parameters are chosen to be close to the parameters of the experiment [S. Cheng , IEEE Trans. Plasma Sci. 24, 750 (1996)ITPSBD0093381310.1109/27.533077], in which a sheet electron beam with the moderate thickness interacts with the TE_{01} mode of a rectangular waveguide. The results strongly indicate that one can improve the efficiency by a factor of 5 or 6 if the FEL operates in the magnetoresonance regime and if the irregular waveguide with the optimized profile is used. The FEL efficiency is maximal if the initial beam energy is slightly higher than the energy that corresponds to a transition between negative and positivemass regimes so that the transition from the negativemass to positivemass regimes occurs during the beamwave interaction.
 Publication:

Physical Review Accelerators and Beams
 Pub Date:
 March 2011
 DOI:
 10.1103/PhysRevSTAB.14.030703
 arXiv:
 arXiv:1004.1373
 Bibcode:
 2011PhRvS..14c0703G
 Keywords:

 41.60.Cr;
 05.45.a;
 84.40.Ik;
 52.59.Sa;
 Freeelectron lasers;
 Nonlinear dynamics and chaos;
 Masers;
 gyrotrons;
 Spacechargedominated beams;
 Physics  Plasma Physics;
 Nonlinear Sciences  Chaotic Dynamics
 EPrint:
 Phys. Rev. STAB 14, 030703 (2011)