Effects of self-fields on gain in two-stream free electron laser with helical wiggler and an axial guiding magnetic field

作     者：Saviz S Lashani E Ashkarran A 

作者机构：Plasma Physics Research CenterScience and Research BranchIslamic Azad University Department of PhysicsFaculty of Basic SciencesUniversity of Mazandaran 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2014年第23卷第2期

页      面：238-241页

核心收录：

学科分类：080901[工学-物理电子学] 070207[理学-光学] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0704[理学-天文学] 0803[工学-光学工程] 0702[理学-物理学] 

主　　题：two stream free electron laser 

摘      要：The theory for the two-stream free electron laser （FEL） consisting of a relativistic electron beam transporting along the axis of a helical wiggler in the presence of an axial guiding magnetic field is proposed and investigated. In the analysis, the effects of self-fields are taken into account. The electron trajectories and the small signal gain are derived. The characteristics of the linear-gain and the normalized maximum gain are studied numerically. The results show that there are seven stable groups of orbits in the presence of self-fields instead of two groups reported in the absence of the self-fields. It is also shown that the normalized gains of three groups decrease while the rest increase with the increasing of normalized cyclotron frequency g20. Furthermore, it is found that the two-stream instability and the self-field lead to a decrease in the maximum gain except for group 3. The results show that the normalized maximum gain is enhanced in comparison with that of the single stream.