Nonlinear Power Saturation and Phase (Wave Refractive Index) in a Collective Free-Electron Laser Amplifier

Fajans, J.; Wurtele, J. S.; Bekefi, G.; Knowles, David S.; Xu, Kaichen

doi:10.1103/physrevlett.57.579

Cited by 57 publications

(10 citation statements)

References 11 publications

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“…This allows the FEL-induced profile modification of the RF field to downconvert to the fundamental TE 10 mode, and a null signal results as shown in Fig. 2d (the other modes excited by the FEL interaction are evanescent and die out exponentially within 1 or 2 waveguide wavelengths from the kicker position).…”

Section: Discussed Below)mentioning

confidence: 99%

Wave profile modification (optical guiding) induced by free-electron laser interaction

Hartemann

Bekefi

et al. 1987

Phys. Rev. Lett.

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Section: Discussed Below)mentioning

confidence: 99%

Wave profile modification (optical guiding) induced by free-electron laser interaction

Hartemann

Bekefi

et al. 1987

Phys. Rev. Lett.

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“…As demonstrated in various experiments (see, for example, Deacon et al, 1977;Warren, Newman, and Goldstein, 1985;Fajans et al, , 1986; Orzechowski et al, 1986), free electron lasers have several remarkable properties, including frequency tunability, high efficiency, high power, and optical guiding by the electron beam (Sprangle and Tang, 1981;Kroll, Morton, and Rosenbluth, 1981;Prosnitz, Szoke, and Neil, 1981;Scharlemann, Sessler, and Wurtele, 1985;Fajans et al, 1986;Tang, 1987a, 1987b). Power levels from hundreds of megawatts to gigawatts have been produced in the infrared (Deacon et al, 1977;Newman et al, 1985) to microwave wavelength range (Parker et al, 1982;Orzechowski et al, 1985Orzechowski et al, , 1986).…”

mentioning

confidence: 99%

Chaotic particle dynamics in free-electron lasers

Chen

Davidson

1991

Phys. Rev. A

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The motion of a relativistic test electron in a free electron laser can be altered significantly by the equilibrium self-field effects produced by the beam space charge and current and by the transverse spatial inhomogeneities in a realizable magnetic wiggler field. In a field configuration consisting of an ideal (constant-amplitude) helical wiggler field and a uniform axial guide field, it is shown that the inclusion of self-field effects destroys the integrability of the particle equations of motion. Consequently, the Group-I orbits and the Group-II orbits become chaotic at sufficiently high beam density. An analytical estimate of the threshold value of the self-field parameter F, = wg/ckw for the onset of chaoticity is obtained and found to be in good agreement with computer simulations. In addition, the effects of transverse spatial gradients in a realizable helical wiggler field with three-dimensional spatial variations are investigated in the absence of an axial guide field, but including self-field effects. For a thin electron beam (k 2r2 < 1) and small wiggler field amplitude (a, < yb 2 ), it is shown that the motion is regular and confined radially provided E, < ybaw/(1 + al). However, because of the intrinsic nonintegrability of the motion, the regular region in phase space diminishes in size as the wiggler amplitude is increased. The threshold value of the wiggler amplitude for the onset of chaoticity is estimated analytically and confirmed by computer simulations for the special case where self-field effects are negligibly small. Moreover, it is shown that the particle motion becomes chaotic on a time scale comparable with the beam transit time through one wiggler period.

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“…Thus, such configurations are quite unlike a conventional FEL where bunching and stimulated emission are fully spatially intermingled. The 2.7m long drift tube acts as a rectangular waveguide whose fundamental TE 10 mode has a cutoff frequency of wc /27r=6.6GHz. Microwaves are launched onto the electron beam by a waveguide coupler (see Fig.…”

Section: Experimental Arrangementmentioning

confidence: 99%

Effects of electron prebunching on the radiation growth rate of a collective (Raman) free-electron laser amplifier

Leibovitch¹,

Bekefi

1988

IEEE J. Quantum Electron.

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Experiments are reported on the effects of electron prebunching in a mildly relativistic, low current (200kV, 1A) free electron laser amplifier operating in the collective (Raman) regime at a frequency of %1OGHz. Prebunching is established by injecting an electromagnetic wave into a bifilar.helical wiggler and then transporting the bunched beam into a second magnetic wiggler region. The wave growth rate is deduced from measurements of the radiation intensity as a function of interaction length. Observations show that prebunching can increase the radiation growth rate manyfold as compared with a system without prebunching. Studies are presented both in the small signal (linear) regime, and in the nonlinear (saturated) regime. tPermanent

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Nonlinear Power Saturation and Phase (Wave Refractive Index) in a Collective Free-Electron Laser Amplifier

Cited by 57 publications

References 11 publications

Wave profile modification (optical guiding) induced by free-electron laser interaction

Wave profile modification (optical guiding) induced by free-electron laser interaction

Chaotic particle dynamics in free-electron lasers

Effects of electron prebunching on the radiation growth rate of a collective (Raman) free-electron laser amplifier

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