The Effect of Fluctuating Space Charge Fields on Sideband Instabilities in Free Electron Lasers
Abstract
We consider the sideband instabilities that can occur in free electron lasers which operate in the regime where the bulk of the energetic electron beam is trapped in the ponderomotive potential generated by the beating of the electromagnetic pulse with the static wiggler field. The general dynamical equations which govern the evolution of the system in the presence of sideband modes are derived for modes propagating along the axis of symmetry. All space-charge effects are included in a self-consistent manner, and the gains for both the primary signal and the upper and lower sidebands are computed. We find the lower sideband to be excited, and discuss the consequences for operation of both free electron laser amplifiers and oscillators. The effect of the space- charge waves on the gain depends upon the number of bounces undergone by the trapped electrons in the length of the system, and can act either to enhance or reduce the gain of the sideband.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 22, 1981
- Accession Number
- ADA111079
Entities
People
- Chai AMei Tang
- H. P. Freund
- Phillip A. Sprangle
Organizations
- United States Naval Research Laboratory