FEL2019 - List of Authors (Vinokurov, N.A.)

Paper	Title	Page
TUP023	Analytical and Numerical Comparison of Different Approaches to the Description of SASE in High Gain FELs	94
	O.A. Shevchenko, N.A. Vinokurov BINP SB RAS, Novosibirsk, Russia N.A. Vinokurov NSU, Novosibirsk, Russia
	Correlation function theory which has been developed recently gives rigorous statistical description of the SASE FEL operation. It directly deals with the values averaged over many shots. There are two other approaches which are based either on Vlasov equation or on direct solution of particle motion equations. Both of them use random functions which relate to single shot. To check the validity of these three approaches it might be interesting to compare them with each other. In this paper we present the results of such comparison obtained for the 1-D FEL model. We show that two-particle correlation function approximation is equivalent to the quasilinear approximation of the Vlasov equation approach. These two approximations are in a good agreement with the results of direct solution of particle motion equations at linear and early saturation stages. To obtain this agreement at strong saturation high order harmonics in Vlasov equation have to be taken into account which corresponds to taking into account of three and more particle correlations in the correlation function approach.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP023
About •	paper received ※ 19 August 2019 paper accepted ※ 25 August 2019 issue date ※ 05 November 2019
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WEP094	Variable-Period Variable-Pole Number Hybrid Undulator Design for Novosibirsk THz FEL	531
	I.V. Davidyuk, O.A. Shevchenko, V.G. Tcheskidov, N.A. Vinokurov BINP SB RAS, Novosibirsk, Russia
	The undulator developed for the first FEL of Novosibirsk FEL facility employs variable-period structure based on the hybrid undulator scheme with poles splinted into halves. The design was adapted to deliver optimal performance, estimations were made based on results of three-dimensional field simulations. According to the modeling results, the undulator will not only widen significantly the first FEL tuning range moving the long-wavelength border of the first harmonic from 200 µm to 450 µm but also provide wider aperture and increase efficiency at shorter wavelengths.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP094
About •	paper received ※ 18 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019
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THP027	Simulation and Optimization of the Transport Beamline for the NovoFEL RF Gun	647
	A.S. Matveev, I.V. Davidyuk, O.A. Shevchenko, V.G. Tcheskidov, N.A. Vinokurov, V. Volkov BINP SB RAS, Novosibirsk, Russia I.V. Davidyuk, A.S. Matveev, N.A. Vinokurov NSU, Novosibirsk, Russia
	A new low-frequency CW RF gun was developed and tested at Budker Institute of Nuclear Physics recently. We plan to use it to upgrade the ERL of the Novosibirsk FEL facility. It will allow increasing the average beam current (due to higher beam repetition rate) and thus increasing the average radiation power. The transport beamline for the RF gun uses the ninety-degree achromatic bend. It is designed in a way that keeps an option to operate with the old electrostatic gun as well. Due to the low beam energy (290 keV) the beam dynamics is strongly influenced by space-charge forces. The paper describes results of simulation and optimization of the RF gun transport beamline. Space-charge forces were taken into account with the code ASTRA. Main sources of emittance degradation were considered in order to decrease their influence during the optimization. In addition, the RF gun output beam parameters were measured for various RF gun emission phases. These experiments were simulated and the results were compared. The resulting beam parameters meets requirements of the Novosibirsk FEL facility ERL.
	Poster THP027 [3.158 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP027
About •	paper received ※ 16 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Analytical and Numerical Comparison of Different Approaches to the Description of SASE in High Gain FELs

94

O.A. Shevchenko, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia
N.A. Vinokurov
NSU, Novosibirsk, Russia

Correlation function theory which has been developed recently gives rigorous statistical description of the SASE FEL operation. It directly deals with the values averaged over many shots. There are two other approaches which are based either on Vlasov equation or on direct solution of particle motion equations. Both of them use random functions which relate to single shot. To check the validity of these three approaches it might be interesting to compare them with each other. In this paper we present the results of such comparison obtained for the 1-D FEL model. We show that two-particle correlation function approximation is equivalent to the quasilinear approximation of the Vlasov equation approach. These two approximations are in a good agreement with the results of direct solution of particle motion equations at linear and early saturation stages. To obtain this agreement at strong saturation high order harmonics in Vlasov equation have to be taken into account which corresponds to taking into account of three and more particle correlations in the correlation function approach.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP023

About •

paper received ※ 19 August 2019 paper accepted ※ 25 August 2019 issue date ※ 05 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP094

Variable-Period Variable-Pole Number Hybrid Undulator Design for Novosibirsk THz FEL

531

I.V. Davidyuk, O.A. Shevchenko, V.G. Tcheskidov, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia

The undulator developed for the first FEL of Novosibirsk FEL facility employs variable-period structure based on the hybrid undulator scheme with poles splinted into halves. The design was adapted to deliver optimal performance, estimations were made based on results of three-dimensional field simulations. According to the modeling results, the undulator will not only widen significantly the first FEL tuning range moving the long-wavelength border of the first harmonic from 200 µm to 450 µm but also provide wider aperture and increase efficiency at shorter wavelengths.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP094

About •

paper received ※ 18 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP027

Simulation and Optimization of the Transport Beamline for the NovoFEL RF Gun

647

A.S. Matveev, I.V. Davidyuk, O.A. Shevchenko, V.G. Tcheskidov, N.A. Vinokurov, V. Volkov
BINP SB RAS, Novosibirsk, Russia
I.V. Davidyuk, A.S. Matveev, N.A. Vinokurov
NSU, Novosibirsk, Russia

A new low-frequency CW RF gun was developed and tested at Budker Institute of Nuclear Physics recently. We plan to use it to upgrade the ERL of the Novosibirsk FEL facility. It will allow increasing the average beam current (due to higher beam repetition rate) and thus increasing the average radiation power. The transport beamline for the RF gun uses the ninety-degree achromatic bend. It is designed in a way that keeps an option to operate with the old electrostatic gun as well. Due to the low beam energy (290 keV) the beam dynamics is strongly influenced by space-charge forces. The paper describes results of simulation and optimization of the RF gun transport beamline. Space-charge forces were taken into account with the code ASTRA. Main sources of emittance degradation were considered in order to decrease their influence during the optimization. In addition, the RF gun output beam parameters were measured for various RF gun emission phases. These experiments were simulated and the results were compared. The resulting beam parameters meets requirements of the Novosibirsk FEL facility ERL.

Poster THP027 [3.158 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP027

About •

paper received ※ 16 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)