Theory of sideband suppression in a tapered free-electron laser

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Bulletin of the American Physical Society

OSTI ID:243592

Pilla, R P; Charjee, A B

Recent experiments and numerical simulations have demonstrated that in a tapered free-electron laser, efficiency enhancement can be accompanied by a strong, and potentially beneficial, reduction in the intensity of parasitic sideband radiation. In this paper, an analytical model is given for this phenomenon. By stability analysis in the nonlinear regime the authors show that a decreasing a{sub W} decreases the maximum sideband growth rate (normalized to the synchrotron period). Since the frequency of the maximal mode (i.e., the sideband with the largest growth rate) varies due to tapering, no single mode can grow at a maximal rate along the undulator, and this permits the formation of only a suppressed but broadened sideband spectrum. Analytical and numerical results will be presented for an optimum undulator profile that maximizes efficiency enhancement with effective sideband suppression.

• OSTI ID: 243592
• Report Number(s): CONF-9304297--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 38; ISSN 0003-0503; ISSN BAPSA6
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
FREE ELECTRON LASERS
MATHEMATICAL MODELS
OSCILLATION MODES
WIGGLER MAGNETS