中国物理B ›› 2012, Vol. 21 ›› Issue (3): 34101-034101.doi: 10.1088/1674-1056/21/3/034101

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Maryam Zahedian,B. Maraghechi,M.H. Rouhani   

  • 收稿日期:2011-08-02 修回日期:2011-09-06 出版日期:2012-02-15 发布日期:2012-02-15
  • 通讯作者: B. Maraghechi,behrouz@aut.ac.ir E-mail:behrouz@aut.ac.ir

Efficiency enhancement of a two-beam free-electron laser using a nonlinearly tapered wiggler

Maryam Zahedian, B. Maraghechi, and M.H. Rouhani   

  1. Department of Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran
  • Received:2011-08-02 Revised:2011-09-06 Online:2012-02-15 Published:2012-02-15
  • Contact: B. Maraghechi,behrouz@aut.ac.ir E-mail:behrouz@aut.ac.ir

Abstract: A nonlinear and non-averaged model of a two-beam free-electron laser (FEL) wiggler that is tapered nonlinearly in the absence of slippage is presented. The two beams are assumed to have different energies, and the fundamental resonance of the higher energy beam is at the third harmonic of the lower energy beam. By using Maxwell's equations and the full Lorentz force equation of motion for the electron beams, coupled differential equations are derived and solved numerically by the fourth-order Runge-Kutta method. The amplitude of the wiggler field is assumed to decrease nonlinearly when the saturation of the third harmonic occurs. By simulation, the optimum starting point of the tapering and the slopes for reducing the wiggler amplitude are found. This technique can be applied to substantially improve the efficiency of the two-beam FEL in the XUV and X-ray regions. The effect of tapering on the dynamical stability of the fast electron beam is also studied.

Key words: free-electron lasers, harmonic generation, Kolmogorov entropy, efficiency enhancement

中图分类号:  (Free-electron lasers)

  • 41.60.Cr
42.65.Ky (Frequency conversion; harmonic generation, including higher-order harmonic generation) 02.60.Cb (Numerical simulation; solution of equations) 94.20.wj (Wave/particle interactions)