Self-Compensation for the Axial Velocity Spread in a Wiggler Field
Abstract
In order to obtain optimal performance from a free electron laser (FEL), the axial velocity spread on the electron beam must be small as it propagates through the wiggler field. Treated separately, both the wiggler-induced betatrons motions and the self-induced space charge forces tend to increase the axial velocity spread and degrade the performance of the FEL. However, it has been shown analytically B. Hafizi and C.W. Roberson, Phys. Plasmas 3, 2156 (1996) that when both effects are treated self-consistently an equilibrium exists wherein the space charge forces exactly compensate for the betatron motion. This leads to the surprising result that for a continuous beam, increasing the beam current can improve the beam quality.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 24, 2002
- Accession Number
- ADP012513
Entities
People
- Bahman Hafizi
- C. W. Roberson
- D. Gordon
- Phillip A. Sprangle
Organizations
- United States Naval Research Laboratory