FEL2019 - List of Authors (Traczykowski, P.)

Paper	Title	Page
TUP049	Simulating Shot-Noise of ’Real’ Electron Bunches	149
	P. Traczykowski, L.T. Campbell, B.W.J. MᶜNeil USTRAT/SUPA, Glasgow, United Kingdom L.T. Campbell, B.W.J. MᶜNeil, P. Traczykowski Cockcroft Institute, Warrington, Cheshire, United Kingdom L.T. Campbell, P. Traczykowski STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	An algorithm and numerical code for the up-sampling of a system of particles, from a smaller to a larger number, is described. The method introduces a Poissonian ’shot-noise’ to the up-sampled distribution [1], typical of the noise statistics arising in a bunch of particles generated by a particle accelerator. The algorithm is applied on a phase-space distribution of relatively few simulation particles representing an electron beam generated by particle accelerator modelling software, for subsequent injection into an Free Electron Laser (FEL) amplifier which is used here to describe the model. A much larger number of particles is usually required to model the FEL lasing process than is required in the simulation models of the electron beam accelerators that drive it. A numerical code developed from the algorithm was then used to generate electron bunches for injection into to an unaveraged 3D FEL simulation code, Puffin [2]. Results show good qualitative and quantitative agreement with analytical theory. The program and usage manual is available to download from GitHub [3]. [1] B.W.J. McNeil, M.W. Poole and G.R.M. Robb, Physical Review Special Topics - Accelerators and Beams Vol 6, 070701 (2003). [2] L.T. Campbell and B.W.J. McNeil, Phys. Plasmas 19, 093119 (2012). [3] https://github.com/UKFELs/JDF
	Poster TUP049 [1.419 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP049
About •	paper received ※ 20 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019
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TUP050	Comparison Between, and Validation Against an Experiment of, a Slowly-varying Envelope Approximation Code and a Particle-in-Cell Simulation Code for Free-Electron Lasers	153
	P. Traczykowski, L.T. Campbell, J. Henderson, B.W.J. MᶜNeil USTRAT/SUPA, Glasgow, United Kingdom L.T. Campbell, J. Henderson, P. Traczykowski STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H. Freund University of New Mexico, Albuquerque, USA B.W.J. MᶜNeil, P. Traczykowski Cockcroft Institute, Warrington, Cheshire, United Kingdom P.J.M. van der Slot Mesa+, Enschede, The Netherlands
	Free-electron laser simulation codes employ either the Slowly-Varying Envelope Approximation (SVEA) or a Particle-in-Cell (PiC) formulation. Maxwell’s equations are averaged over the fast time scale in the SVEA so that there is no need to resolve the wave period. In contrast, the fast oscillation is retained in PiC codes. As a result, the SVEA codes are much less computationally intensive and are used more frequently than PiC codes. While the orbit dynamics in PiC codes and some SVEA Codes (MEDUSA and MINERVA) use the full unaveraged Lorentz force equations, some SVEA codes use the Kroll-Morton-Rosenbluth (KMR) approximation (GENESIS, GINGER, FAST, and TDA3D). Steady-state simulation comparisons [1] have appeared in the literature between different codes using the averaged and unaveraged particle dynamics. Recently, a comparison between three KMR SVEA codes (GENESIS, GINGER, and FAST) and the PUFFIN PiC code in the time-dependent regime has been reported [2]. In this paper, we present a comparison between the unaveraged PiC code PUFFIN, the unaveraged SVEA code MINERVA for the time-dependent simulation of SASE free-electron lasers with the experimental measurements from SPARC SASE FEL at ENEA Frascati. [1] S.G. Biedron et al., NIMA 445, 110 (2000). [2] B. Garcia et al., paper presented at the 38th International Free Electron Laser Conference, Santa Fe, New Mexico, 20 - 25 August 2017.
	Poster TUP050 [0.908 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP050
About •	paper received ※ 02 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP051	Plasma Accelerator Driven Coherent Spontaneous Emission	157
	B.M. Alotaibi, R. Altuijri PNU, Riyadh, Kingdom of Saudi Arabia B.M. Alotaibi, R. Altuijri, A.F. Habib, B. Hidding, B.W.J. MᶜNeil, P. Traczykowski USTRAT/SUPA, Glasgow, United Kingdom A.F. Habib, B. Hidding, B.W.J. MᶜNeil, P. Traczykowski Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Plasma accelerators [1] are a potentially important source of high energy, low emittance electron beams with high peak currents generated within a relatively short distance. As such, they may have an important application in the driving of coherent light sources such as the Free Electron Laser (FEL) which operate into the X-ray region [2]. While novel plasma photocathodes [3] may offer orders of magnitude improvement to the normalized emittance and brightness of electron beams compared to Radio Frequency-driven accelerators, a substantial challenge is the energy spread and chirp of beams, which can make FEL operation impossible. In this paper it is shown that such an energy-chirped, ultrahigh brightness electron beam, with dynamically evolving current profile due to ballistic bunching at moderate energies, can generate significant coherent radiation output via the process of Coherent Spontaneous Emission (CSE)[4]. While this CSE is seen to cause some FEL-induced electron bunching at the radiation wavelength, the dynamic evolution of the energy chirped pulse dampens out any high-gain FEL interaction. [1] E. Esary et al., Reviews of Modern Physics p. 1229 (2009). [2] B. W. J. McNeil and N. R. Thompson, 2010 Nat. Photon.4 814-21 [3] B. Hidding et al., 2012 Phys. Rev. Lett. 108 035001 [4] L. T. Campbell and B. W. J. McNeil, 2012, in Proc. FEL2012
	Poster TUP051 [1.401 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP051
About •	paper received ※ 20 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

Simulating Shot-Noise of ’Real’ Electron Bunches

149

P. Traczykowski, L.T. Campbell, B.W.J. MᶜNeil
USTRAT/SUPA, Glasgow, United Kingdom
L.T. Campbell, B.W.J. MᶜNeil, P. Traczykowski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L.T. Campbell, P. Traczykowski
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

An algorithm and numerical code for the up-sampling of a system of particles, from a smaller to a larger number, is described. The method introduces a Poissonian ’shot-noise’ to the up-sampled distribution [1], typical of the noise statistics arising in a bunch of particles generated by a particle accelerator. The algorithm is applied on a phase-space distribution of relatively few simulation particles representing an electron beam generated by particle accelerator modelling software, for subsequent injection into an Free Electron Laser (FEL) amplifier which is used here to describe the model. A much larger number of particles is usually required to model the FEL lasing process than is required in the simulation models of the electron beam accelerators that drive it. A numerical code developed from the algorithm was then used to generate electron bunches for injection into to an unaveraged 3D FEL simulation code, Puffin [2]. Results show good qualitative and quantitative agreement with analytical theory. The program and usage manual is available to download from GitHub [3].
[1] B.W.J. McNeil, M.W. Poole and G.R.M. Robb, Physical Review Special Topics - Accelerators and Beams Vol 6, 070701 (2003).
[2] L.T. Campbell and B.W.J. McNeil, Phys. Plasmas 19, 093119 (2012).
[3] https://github.com/UKFELs/JDF

Poster TUP049 [1.419 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP049

About •

paper received ※ 20 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)

TUP050

Comparison Between, and Validation Against an Experiment of, a Slowly-varying Envelope Approximation Code and a Particle-in-Cell Simulation Code for Free-Electron Lasers

153

P. Traczykowski, L.T. Campbell, J. Henderson, B.W.J. MᶜNeil
USTRAT/SUPA, Glasgow, United Kingdom
L.T. Campbell, J. Henderson, P. Traczykowski
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H. Freund
University of New Mexico, Albuquerque, USA
B.W.J. MᶜNeil, P. Traczykowski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
P.J.M. van der Slot
Mesa+, Enschede, The Netherlands

Free-electron laser simulation codes employ either the Slowly-Varying Envelope Approximation (SVEA) or a Particle-in-Cell (PiC) formulation. Maxwell’s equations are averaged over the fast time scale in the SVEA so that there is no need to resolve the wave period. In contrast, the fast oscillation is retained in PiC codes. As a result, the SVEA codes are much less computationally intensive and are used more frequently than PiC codes. While the orbit dynamics in PiC codes and some SVEA Codes (MEDUSA and MINERVA) use the full unaveraged Lorentz force equations, some SVEA codes use the Kroll-Morton-Rosenbluth (KMR) approximation (GENESIS, GINGER, FAST, and TDA3D). Steady-state simulation comparisons [1] have appeared in the literature between different codes using the averaged and unaveraged particle dynamics. Recently, a comparison between three KMR SVEA codes (GENESIS, GINGER, and FAST) and the PUFFIN PiC code in the time-dependent regime has been reported [2]. In this paper, we present a comparison between the unaveraged PiC code PUFFIN, the unaveraged SVEA code MINERVA for the time-dependent simulation of SASE free-electron lasers with the experimental measurements from SPARC SASE FEL at ENEA Frascati.
[1] S.G. Biedron et al., NIMA 445, 110 (2000).
[2] B. Garcia et al., paper presented at the 38th International Free Electron Laser Conference, Santa Fe, New Mexico, 20 - 25 August 2017.

Poster TUP050 [0.908 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP050

About •

paper received ※ 02 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019

Export •

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

TUP051

Plasma Accelerator Driven Coherent Spontaneous Emission

157

B.M. Alotaibi, R. Altuijri
PNU, Riyadh, Kingdom of Saudi Arabia
B.M. Alotaibi, R. Altuijri, A.F. Habib, B. Hidding, B.W.J. MᶜNeil, P. Traczykowski
USTRAT/SUPA, Glasgow, United Kingdom
A.F. Habib, B. Hidding, B.W.J. MᶜNeil, P. Traczykowski
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Plasma accelerators [1] are a potentially important source of high energy, low emittance electron beams with high peak currents generated within a relatively short distance. As such, they may have an important application in the driving of coherent light sources such as the Free Electron Laser (FEL) which operate into the X-ray region [2]. While novel plasma photocathodes [3] may offer orders of magnitude improvement to the normalized emittance and brightness of electron beams compared to Radio Frequency-driven accelerators, a substantial challenge is the energy spread and chirp of beams, which can make FEL operation impossible. In this paper it is shown that such an energy-chirped, ultrahigh brightness electron beam, with dynamically evolving current profile due to ballistic bunching at moderate energies, can generate significant coherent radiation output via the process of Coherent Spontaneous Emission (CSE)[4]. While this CSE is seen to cause some FEL-induced electron bunching at the radiation wavelength, the dynamic evolution of the energy chirped pulse dampens out any high-gain FEL interaction.
[1] E. Esary et al., Reviews of Modern Physics p. 1229 (2009).
[2] B. W. J. McNeil and N. R. Thompson, 2010 Nat. Photon.4 814-21
[3] B. Hidding et al., 2012 Phys. Rev. Lett. 108 035001
[4] L. T. Campbell and B. W. J. McNeil, 2012, in Proc. FEL2012

Poster TUP051 [1.401 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP051

About •

paper received ※ 20 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)