A multimode small signal analysis of the single pass free electron laser

Dattoli, G.; Marino, A.; Renieri, A.

doi:10.1016/0030-4018(80)90062-0

Cited by 43 publications

(5 citation statements)

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“…The linear regime has been studied numerically for an arbitrary beam profile y(u) in Ref. [13] and analytically in the long-bunch approximation, Lp )) A, in Refs. [14,15].…”

Section: The Reduced Modelmentioning

confidence: 99%

Analytical theory of short-pulse free-electron laser oscillators

et al. 1995

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A simple model for the nonlinear evolution of a short-pulse free-electron laser oscillator in the small gain regime is derived. An analysis of the linearized system allows the definition and calculation of the eigenmodes characterizing the small signal regime. An arbitrary solution of the nonlinear system can then be expanded in terms of these supermodes. In the single-supermode approximation, the system reduces to a Landau-Ginzburg equation, which allows the efBciency and saturated power to be obtained as functions of cavity detuning and cavity losses. In the limit of small cavity detuning, electrons emit superradiantly, with an efBciency inversely proportional to the number of radiation wavelengths within the optical pulse, and power proportional to the square of the bunch charge. In the multisupermode regime, limit cycles and period doubling behavior are observed and interpreted as a competition between supermodes. Finally, the analytical and numerical results are compared with the experimental observations from the Free-Electron Laser for Infrared eXperiments experiment.

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“…The linear regime has been studied numerically for an arbitrary beam profile y(u) in Ref. [13] and analytically in the long-bunch approximation, Lp )) A, in Refs. [14,15].…”

Section: The Reduced Modelmentioning

confidence: 99%

Analytical theory of short-pulse free-electron laser oscillators

et al. 1995

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“…This negative slippage provides a positive feedback with bunching and power carried by the electrons and radiation in counterpropagating directions, leading to self-modulation of the emitted intensity [8]. A positive detuning b allows for the existence in the linear regime of stationary solutions of the form A(z2, w) = exp(pw)A, (z2), where p is the complex eigenvalue with positive real part [6]. These solutions represent stable pulse configurations whose intensity is multiplied each pass by a constant gain factor.…”

mentioning

confidence: 99%

“…Although no stable configurations exist in the linear regime for exact synchronism [6], it is important to investigate the transient regime in this case. We assume in the rest of the analysis b = 0, reserving the analysis of the more complex case with positive cavity detuning b to a further publication.…”

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confidence: 99%

Transient regime and superradiance in a short-pulse free-electron-laser oscillator

Piovella

1995

Phys. Rev. E

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We investigate the transient evolution of radiation in a low-gain free-electron-laser oscillator, driven by synchronized electron bunches much shorter than the slippage. We calculate analytically the radiation intensity and the gain in the linear regime. We show that, in the nonlinear regime and in the ideal case without losses, the radiation 6eld is described, as in the short-pulse, high-gain ampli6er, by the self-similar superradiant solution.PACS number(s): 41.60.Cr, 42.60.Jf Recently increasing interest has been given to &eeelectron-laser oscillators driven by electron bunches shorter than or equal to the slippage distance [1,2]. In particular, superrad. iant emission of short radiation pulses, whose peak intensity is proportional to the square of the electron beam density [3], has been observed numerically [4] for pulse length equal to the slippage distance. Superradiance has been supposed to play a role in several efFects occurring in the short-pulse operation, for example, the observation of limit cycles in a d.esynchronized cavity, with a periodic generation of radiation pulses [5]. At present, however, superradiant emission in oscillators has not yet been demonstrated analytically. Moreover, theoretical works dealing with shortpulse propagation, apart &om numerical simulations, have been focused only on the research of stationary solutions, called supermodes [6], and not on the transient regime.

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“…The lasing at negative cavity-length detuning (δL < 0) has been studied analytically by supermode theory [7,8,11]. The analytical studies revealed that the lasing behavior of short-pulse FELs, in which the bunch length is shorter than the slippage distance, shows various aspects according to the gain, loss, and cavity length detuning: single supermode lasing with a smooth temporal profile, limit cycle lasing with a multi-peak pulse, and chaotic lasing with many spikes in a pulse.…”

Section: Experiments At Jaeri-felmentioning

confidence: 99%

Few-Cycle Infrared Pulse Evolving in FEL Oscillators and Its Application to High-Harmonic Generation for Attosecond Ultraviolet and X-ray Pulses

Hajima

2021

Atoms

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Generation of few-cycle optical pulses in free-electron laser (FEL) oscillators has been experimentally demonstrated in FEL facilities based on normal-conducting and superconducting linear accelerators. Analytical and numerical studies have revealed that the few-cycle FEL lasing can be explained in the frame of superradiance, cooperative emission from self-bunched systems. In the present paper, we review historical remarks of superradiance FEL experiments in short-pulse FEL oscillators with emphasis on the few-cycle pulse generation and discuss the application of the few-cycle FEL pulses to the scheme of FEL-HHG, utilization of infrared FEL pulses to drive high-harmonic generation (HHG) from gas and solid targets. The FEL-HHG enables one to explore ultrafast science with attosecond ultraviolet and X-ray pulses with a MHz repetition rate, which is difficult with HHG driven by solid-state lasers. A research program has been launched to develop technologies for the FEL-HHG and to conduct a proof-of-concept experiment of FEL-HHG.

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A multimode small signal analysis of the single pass free electron laser

Cited by 43 publications

References 5 publications

Analytical theory of short-pulse free-electron laser oscillators

Analytical theory of short-pulse free-electron laser oscillators

Transient regime and superradiance in a short-pulse free-electron-laser oscillator

Few-Cycle Infrared Pulse Evolving in FEL Oscillators and Its Application to High-Harmonic Generation for Attosecond Ultraviolet and X-ray Pulses

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