The Gain-Spread-Excitation Theorem
Abstract
This paper proposed an extension of the Madey gain-spread theorem to two-dimensional wigglers and shown it to be quite generally valid. It has the important consequence that an Free Electron Laser(FEL) wiggler which yields gain must at the same time generate either energy spread or transverse excitation. Furthermore it was found that in an FEL operating quasi linearly in a storage ring, that laser gain guarantees the production of entropy with every pass through the wiggler. Consequently the laser radiation generated is restricted to be some small fraction of the synchrotron radiation and our analysis suggests that this fraction is of the order of the fractional energy aperture. This leads us to the conclusion that the achievement of high efficiency steady stage storage ring operation in a quasi linear regime is not possible. Nonetheless, it appears that gain expanded wigglers may have superior linear gain as compared with conventional wigglers and thus prove to be useful for application in storage rings with large fractional energy aperture.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1984
- Accession Number
- ADA144447
Entities
People
- M. Rosenbluth
- N. Kroll
Organizations
- MITRE Corporation