Gauss-Laguerre modes in a high-grain FEL

Best, R.W.B.; Faatz, B.

doi:10.1088/0022-3727/23/11/001

Cited by 11 publications

(5 citation statements)

References 4 publications

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“…Thus the number of modes with significant amplitude can be high if the source point is not chosen well. To avoid this problem an optimization algorithm could change the source point per integration step so that the number of modes stays low (Best and Faatz, 1990). Another drawback is the calculation of the source term.…”

Section: Equation Section 8viii Numerical Codesmentioning

confidence: 99%

The physics of x-ray free-electron lasers

2016

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X-ray Free-electron Lasers (X-ray FELs) give us for the first time the possibility to explore structures and dynamical processes of atomic and molecular systems at the Ångstrom-femtosecond space and time scales. They generate coherent photon pulses with time duration of a few to 100 femtosecond, peak power of 10 to 100 GW, over a wavelength range extending from about 100 nm to less than 1 Å. Using these novel and unique capabilities new scientific results are being obtained in atomic and molecular sciences, in areas of physics, chemistry and biology. In this paper we review the physical principles, the theoretical models and the numerical codes on which X-ray FELs are based, starting from a single electron spontaneous undulator radiation to the FEL collective instability of a high density electron beam, strongly enhancing the electromagnetic radiation field intensity and its coherence properties. We present also a short review of the main experimental properties of X-ray FELs, and discuss the results of the most recent research to improve their longitudinal coherence properties, increase the peak power and generate multicolor spectra.

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Section: Equation Section 8viii Numerical Codesmentioning

confidence: 99%

The physics of x-ray free-electron lasers

2016

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“…In the simulation, the equation of motion is described using an axis-symmetric beam field Aðx; zÞ decomposed into Gauss-Laguerre modes 26) as…”

Section: The Modelmentioning

confidence: 99%

Transverse effects in a free-electron laser oscillator with two electron beams

Nam¹

2015

Jpn. J. Appl. Phys.

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We have analyzed the transverse effects in a free-electron laser (FEL) oscillator using two electron beams of different energies referring to a proposed FEL facility operated in the far-infrared and infrared regions. The transverse effects in a free-electron laser oscillator were studied taking into account the electron beam’s emittance, offset misalignment errors, energy spreads, and higher-order modes using an extended two-dimensional (2D) FEL code with two electron beams that we developed. The variation in the radiation amplitude depending on the electron beam emittance, offset misalignment errors, and energy spreads was also calculated in the case of betatron oscillations for multiparticles and multipass numbers using a new 2D code. The mode construction was studied for higher-order modes of the wiggler with and without offset misalignment errors for FEL operation with a high-quality electron beam.

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“…By assuming both beams have the same transverse cross-section are obtained the second equalities of Eqs. (8) and (9) in terms of the beam currents. The coupling of the lower energy electrons to both the fundamental and harmonic fields is seen in Eq.…”

Section: The Modelmentioning

confidence: 99%

“…Equation (6) demonstrates that the harmonic field has two driving sources: the lower-and the higherenergy electron beams. In the simulation, the equation of motion is described using an axis-symmetric beam field A(x,z) decomposed into Gauss-Laguerre modes [9] as…”

Section: The Modelmentioning

confidence: 99%

The effects of two electron beams on a free-electron laser oscillator

Nam

2014

Journal of the Korean Physical Society

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We have analyzed the characteristics of a free-electron laser (FEL) oscillator by using two electron beams of different energies. The evolution of the harmonic output intensity of the two-beam oscillator, the harmonic radiation field intensity relative to the beam's current ratio, the harmonic field obtained by using both the lower and the higher electron energy beams, and the harmonic field for the higher energy electron beam alone were studied by using an extended 2D simulation code that described the effects of two electron beams with different energies. The 2D effects of the energy spread, higher-order modes, and the transverse mode construction of the optical field were also studied in the two electron beam oscillator model for the low-energy region.

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Gauss-Laguerre modes in a high-grain FEL

Abstract: A decomposition is made, in axisymmetric Gauss-Laguerre modes, of the bumpy optical beam shape in a high-grain free electron laser. It is shown that waist position and Rayleigh length can be chosen freely over a wide range of values. A method to optimize the choice is given.

Cited by 11 publications

References 4 publications

The physics of x-ray free-electron lasers

The physics of x-ray free-electron lasers

Transverse effects in a free-electron laser oscillator with two electron beams

The effects of two electron beams on a free-electron laser oscillator

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