中国物理B ›› 2011, Vol. 20 ›› Issue (7): 74101-074101.doi: 10.1088/1674-1056/20/7/074101

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Effects of self-fields on electron trajectory and gain in two-stream electromagnetically pumped free-electron laser with ion channel guiding

H. Mehdian1, Farzin M. Aghamir2, S. Saviz3, M. Ghorannevis3   

  1. (1)Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49, Dr. Mofatteh avenue, Tehran 15614, Iran; (2)Department of Physics, University of Tehran, N. Kargar Ave, Tehran 14399, Iran; (3)Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, P.O. Box. 14665-678, Iran
  • 收稿日期:2010-04-19 修回日期:2011-01-23 出版日期:2011-07-15 发布日期:2011-07-15

Effects of self-fields on electron trajectory and gain in two-stream electromagnetically pumped free-electron laser with ion channel guiding

S. Saviza)†, Farzin M. Aghamirb), H. Mehdianc), and M. Ghorannevisa)   

  1. a Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, P.O. Box. 14665-678, Iran; b Department of Physics, University of Tehran, N. Kargar Ave, Tehran 14399, Iran; c Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49, Dr. Mofatteh avenue, Tehran 15614, Iran
  • Received:2010-04-19 Revised:2011-01-23 Online:2011-07-15 Published:2011-07-15

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摘要： A theory for the two-stream free-electron laser with an electromagnetic wiggler (EMW) and an ion channel guiding is developed. In the analysis, the effects of self-fields have been taken into account. The electron trajectories and the small signal gain are derived. The stability of the trajectories, the characteristics of the linear gain and the normalized maximum gain are studied numerically. The dependence of the normalized frequency ω corresponding to the maximum gain on the ion-channel frequency is presented. The results show that there are seven groups of orbits in the presence of the self-fields, which are similar to those reported in the absence of the self-fields. It is also shown that the normalized gains of 2 groups decrease while the rest increase with the increasing normalized ion-channel frequency. Furthermore, it is found that the two-stream instability and the self-field lead to a decrease in the maximum gain except for group 4.

关键词: free electron laser, two-stream

Abstract: A theory for the two-stream free-electron laser with an electromagnetic wiggler (EMW) and an ion channel guiding is developed. In the analysis, the effects of self-fields have been taken into account. The electron trajectories and the small signal gain are derived. The stability of the trajectories, the characteristics of the linear gain and the normalized maximum gain are studied numerically. The dependence of the normalized frequency $\hat{\omega}$ corresponding to the maximum gain on the ion-channel frequency is presented. The results show that there are seven groups of orbits in the presence of the self-fields, which are similar to those reported in the absence of the self-fields. It is also shown that the normalized gains of 2 groups decrease while the rest increase with the increasing normalized ion-channel frequency. Furthermore, it is found that the two-stream instability and the self-field lead to a decrease in the maximum gain except for group 4.

Key words: free electron laser, two-stream

中图分类号:  (Free-electron lasers)

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