| Numéro |
J. Phys. Colloques
Volume 44, Numéro C1, Février 1983
Conférence de Bendor sur les Lasers à Electrons Libres / Bendor Free Electron Laser Conference
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|---|---|---|
| Page(s) | C1-371 - C1-371 | |
| DOI | https://doi.org/10.1051/jphyscol:1983132 | |
J. Phys. Colloques 44 (1983) C1-371-C1-371
DOI: 10.1051/jphyscol:1983132
TAPERED WIGGLER FREE ELECTRON LASERS DRIVEN BY NON-MONOENERGETIC ELECTRON BEAMS
J.C. Goldstein1, W.B. Colson2 et R.W. Warren11 University of California, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, U.S.A.
2 Quantum Institute, University of California at Santa Barbara, Santa Barbara, CA 93106, U.S.A.
Abstract
Theoretical results are presented for two distinct but related problems, both involving the excitation of a tapered wiggler FEL by nonmonoenergetic electron beams : (I) A comparison between calculated and measured electron energy spectra for the Los Alamos tapered wiggler FEL amplifier experiment is given. Using the measured incident electron distribution and wiggler parameters, calculated electron energy distributions after interaction with the optical and wiggler fields are compared with measured data as a function of the mean energy of the incident beam. Best agreement is found in the region of maximum extraction efficiency. (II) Calculations of oscillator performance of a tapered wiggler FEL excited by 10 ps electron beam pulse are presented. Results for a monoenergetic electron beam are compared to those for an initial beam having a .5% energy spread. The laser is operated in a high cavity loss regime. This leads to less severely modulated optical pulses due to lower steady state intensities and decreased growth of sideband frequencies. The desynchronism curve for the monoenergetic case is found to be the slightly wider one, as expected from the depression of the small signal gain for a nonmonoenergetic electron beam. High intensity properties are very similar for the two cases.