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Ali Akbar Ashkarran

Ali Akbar Ashkarran

Academic rank: Assistant Professor
ORCID:
Education: PhD.
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Faculty:
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Phone: 01135302485

Research

Title
Effects of self-fields on gain in two-stream free electron laser with helical wiggler and an axial guiding magnetic field
Type
JournalPaper
Keywords
two-stream free electron laser
Year
2013
Journal Chinese Physics B
DOI
Researchers Shahrooz Saviz ، E Lashani ، Ali Akbar Ashkarran

Abstract

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 W0. 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.