Pulse slippage in high-gain, optically guided free-electron lasers

Hafizi, B.; Sprangle, P.; Peñano, Joseph

doi:10.1016/j.nima.2007.08.166

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…The aim of this paper is to present a three-dimensional simulation of the emission at the fundamental and third harmonic in the non-wiggler-averaged-orbit approximation of the harmonic lasing FEL with source-dependent expansion [40][41][42][43]. Therefore, the source function is incorporated self-consistently into the functional dependence of the radiation waist, the radiation wavefront curvature, and the radiation amplitude instead of using the usual modal expansion consisting of vacuum Laguerre-Gaussian or Hermite-Gaussian functions.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

2016

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Detuning of the fundamental is a way to enhance harmonic generation . By this method, the wiggler is composed of two segments in such a way that the fundamental resonance of the second segment to coincide with the third harmonic of the first segment of the wiggler to generate extreme ultraviolet radiation and x-ray emission. A set of coupled, nonlinear, and first-order differential equations in three dimensions describing the evolution of the electron trajectories and the radiation field with warm beam is solved numerically by CYRUS 3D code in the steady-state for two models (1) seeded free electron laser (FEL) and (2) shot noise on the electron beam (self-amplified spontaneous emission FEL). Thermal effects in the form of longitudinal velocity spread is considered. Three-dimensional simulation describes self-consistently the longitudinal spatial dependence of radiation waists, curvatures, and amplitudes together with the evaluation of the electron beam. The evolutions of the transverse modes are investigated for the fundamental resonance and the third harmonic. Also, the effective modes of the third harmonic are studied. In this paper, we found that detuning of the fundamental with shot noise gives more optimistic result than the seeded FEL. * Electronic address: behrouz@aut.ac.ir 1 arXiv:1603.05799v1 [physics.acc-ph]

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Section: Introductionmentioning

confidence: 99%

Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

2016

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“…The purpose of the present study is to present a threedimensional nonaveraged simulation of two-beam FEL by using source-dependent expansion (SDE) [18][19][20][21][22]. The novel aspect of the SDE method is that the characteristics of the modes are governed by the driving current density.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional simulation of harmonic up-conversion in a prebunched two-beam free-electron laser

Rouhani

Maraghechi

2010

Phys. Rev. ST Accel. Beams

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Three-dimensional simulation of harmonic up-conversion in a free-electron laser amplifier operating simultaneously with two cold and relativistic electron beams with different energy is presented in the steady-state regime. The fundamental resonance of the higher energy beam is adjusted at the third harmonic of the lower energy beam. By using slowly varying envelope approximation, the hyperbolic wave equations can be transformed into parabolic diffusion equations. By applying the source-dependent expansion to these equations, electromagnetic fields are represented in terms of the Hermite Gaussian modes which are well suited for the planar wiggler configuration. The electron dynamics is described by the fully three-dimensional Lorentz force equation in the presence of the realistic planar magnetostatic wiggler and electromagnetic fields. A set of coupled nonlinear first-order differential equations is derived and solved numerically. This set of equations describes self-consistently the longitudinal spatial dependence of radiation waists, curvatures, and amplitudes together with the evaluation of the electron beam. The evolutions of the transverse modes, in this system, are investigated for the fundamental resonance and its harmonic up-conversion. In addition to uniform beam, prebunched electron beam has also been studied. The effect of sinusoidal distribution of entry times for low energy electron beam on the evolution of radiation is compared with water bag distribution. It is shown that prebunching reduces the saturation length substantially. The analysis is related to extreme ultraviolet and x-ray emission where by seeding the lower frequency of the fundamental resonance of the lower energy beam substantial power is obtained at its third harmonic.

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Pulse slippage in high-gain, optically guided free-electron lasers

Cited by 2 publications

References 16 publications

Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

Three-dimensional simulation of harmonic up-conversion in a prebunched two-beam free-electron laser

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