Effect of Energy and Density Separation of Electron Beams on the Peak Growths and Wavenumbers in a Free-electron Laser with Two Relativistic Beams and a Helical Undulator

Study of Free-electron Laser with Two Beams

  • Maryam Razaghzadeh Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad, Iran
  • Nader Mahdizadeh Department of Physics, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran
  • Alireza Haghpeima Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad, Iran
  • Babak Haghighi Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Keywords: free-electron laser, relativistic electron beams, dispersion relation, peak growth, resonance band, water-bag distribution function

Abstract

This article is devoted to the study of the free-electron laser (FEL) employing two relativistic electron beams and a helical undulator. Our study is based on the framework of kinetic description. By using the first order principle the dispersion relation (DR) which has shown the resonance bands is obtained. To generality a water bag distribution function (DF) for electron beams is considered. Using the iteration method by numerical solution DR for the electromagnetic mode and space charge mode has been solved. It has shown that increasing the energy separation of two electron currents results in decreasing the peak growth and causes to increase in the wave number of the FEL resonance, while it has the opposite behaviour for two stream FEL resonance. It has been noticed that the coupling of the electromagnetic wave (EMW) with the space charge wave leads to the instabilities.

 

Published
2025-03-10
Issue
Vol 68 No 1 (2025): Pakistan Journal of Scientific and Industrial Research Series A: Physical Sciences
Section
Articles