IPAC2019 - List of Authors (Cook, N.M.)

Paper	Title	Page
WEPTS068	A Novel S-Based Symplectic Algorithm for Tracking With Space Charge	3279
	J.P. Edelen, D.T. Abell, D.L. Bruhwiler, N.M. Cook, C.C. Hall, S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0011340 Traditional finite-difference particle-in-cell methods for modeling self-consistent space charge introduce non-Hamiltonian effects that make long-term tracking in storage rings unreliable. Foremost of these is so-called grid heating. Particularly for studies where the Hamiltonian invariants are critical for understanding the beam dynamics, such as nonlinear integrable optics, these spurious effects make interpreting simulation results difficult. To remedy this, we present a novel symplectic spectral space charge algorithm that is free of non-Hamiltonian numerical effects and, therefore, suitable for long-term tracking studies. Results presented here include a detailed study of the solver’s performance under a range of conditions. First, we show benchmarking and convergence studies for different particle shapes and different particle distributions. Then we demonstrate the solver’s ability to preserve Hamiltonian structure by studying the formation of space-charge driven resonances using both our algorithm and traditional PIC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS068
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMP046	Knowledge Exchange Within the Particle Accelerator Community via Cloud Computing	3548
	D.L. Bruhwiler, D.T. Abell, N.M. Cook, C.C. Hall, M.V. Keilman, P. Moeller, R. Nagler, B. Nash RadiaSoft LLC, Boulder, Colorado, USA
	Funding: Work supported by US Department of Energy under Award Nos. DE-SC0011237, DE-SC0011340, DE-SC0018719, DE-SC0015212, DE-SC0017181 and DE-SC0017162. The development, testing and use of particle accelerator modeling codes is a core competency of accelerator research laboratories around the world, and likewise for synchrotron radiation and X-ray optics codes at lightsource facilities. Such codes require time and training to learn a command-line workflow involving multiple input and configuration files, execution on a high-performance server or cluster, post-processing with specialized software and finally visualization. Such workflows are error prone an difficult to reproduce. Cloud computing and UI design are core competencies of RadiaSoft LLC, where the Sirepo* framework is being developed to make state of the art codes available in the browser of any desktop, laptop or tablet. We present our initial successes as real world examples of knowledge exchange (KE) between industry and the research community. This work is leading to broader knowledge exchange throughout the community by facilitating education of students and enabling instantaneous sharing of simulation details between colleagues. Sirepo design objectives include: seamless integration with legacy codes, low barrier to entry for new users, configuration transfer to command line mode, catalog of provenance to aid reproducibility, and simplified collaboration through multimodal sharing. The Sirepo Scientific Gateway** allows users to directly test the software. The combination of intuitive browser-based GUIs and Sirepo’s server-side application container technology enables simplified computational archiving and reproducibility. If embraced by the community, this could become an important asset for the design, commissioning and future upgrade of particle accelerator and X-ray beamline facilities. * Sirepo cloud computing framework, https://github.com/radiasoft/sirepo ** Sirepo Scientific Gateway, https://sirepo.com
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP046
About •	paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMP047	Advanced Modeling and Optimization of Thermionic Energy Converters	3552
	J.P. Edelen, N.M. Cook, C.C. Hall, Y. Hu RadiaSoft LLC, Boulder, Colorado, USA J.-L. Vay LBNL, Berkeley, California, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0017162 Thermionic energy converters (TEC) are a class of thermoelectric devices, which promise improvements to the efficiency and cost of both small- and large-scale electricity generation. A TEC is comprised of a narrowly-separated thermionic emitter and an anode. Simple structures are often space-charge limited as operating temperatures produce currents exceeding the Child-Langmuir limit. We present results from 3D simulations of these devices using the particle-in-cell code Warp, developed at Lawrence Berkeley National Lab. We demonstrate improvements to the Warp code permitting high fidelity simulations of complex device geometries. These improvements include modeling of non-conformal geometries using mesh refinement and cut-cells with a dielectric solver, in addition to importing geometries directly from standard CAD output. In this paper we showcase some of these new features and demonstrate their use.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP047
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPGW073	Status on a Laser Injection in Beam Driven Dielectric Wakefield Accelerator Experiment	3761
	G. Andonian, T.J. Campese, F.H. O’Shea RadiaBeam, Santa Monica, California, USA D.L. Bruhwiler, N.M. Cook RadiaSoft LLC, Boulder, Colorado, USA M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski ANL, Argonne, Illinois, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA T. Xu Northern Illinois University, DeKalb, Illinois, USA
	The generation of high-brightness beams with ultra-low emittance using the plasma photocathode technique has gained significant traction in recent years. The practical execution of a combined plasma wakefield acceleration section and a laser injected typically requires a dual gas medium for precision ionization of low and high ionization thresholds. The concept can be partially simplified in experiment by replacing the plasma wakefield acceleration component with a dielectric wakefield acceleration scheme, sacrificing field gradient but maintaining low emittance beam generation. In this paper, we describe the progress on the design of a hybrid scheme, using laser injection in a gas medium within a dielectric wakefield accelerator structure. The proof-of-concept experiment is planned to take place at the Argonne Wakefield Accelerator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW073
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

A Novel S-Based Symplectic Algorithm for Tracking With Space Charge

3279

J.P. Edelen, D.T. Abell, D.L. Bruhwiler, N.M. Cook, C.C. Hall, S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0011340
Traditional finite-difference particle-in-cell methods for modeling self-consistent space charge introduce non-Hamiltonian effects that make long-term tracking in storage rings unreliable. Foremost of these is so-called grid heating. Particularly for studies where the Hamiltonian invariants are critical for understanding the beam dynamics, such as nonlinear integrable optics, these spurious effects make interpreting simulation results difficult. To remedy this, we present a novel symplectic spectral space charge algorithm that is free of non-Hamiltonian numerical effects and, therefore, suitable for long-term tracking studies. Results presented here include a detailed study of the solver’s performance under a range of conditions. First, we show benchmarking and convergence studies for different particle shapes and different particle distributions. Then we demonstrate the solver’s ability to preserve Hamiltonian structure by studying the formation of space-charge driven resonances using both our algorithm and traditional PIC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS068

About •

paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

THPMP046

Knowledge Exchange Within the Particle Accelerator Community via Cloud Computing

3548

D.L. Bruhwiler, D.T. Abell, N.M. Cook, C.C. Hall, M.V. Keilman, P. Moeller, R. Nagler, B. Nash
RadiaSoft LLC, Boulder, Colorado, USA

Funding: Work supported by US Department of Energy under Award Nos. DE-SC0011237, DE-SC0011340, DE-SC0018719, DE-SC0015212, DE-SC0017181 and DE-SC0017162.
The development, testing and use of particle accelerator modeling codes is a core competency of accelerator research laboratories around the world, and likewise for synchrotron radiation and X-ray optics codes at lightsource facilities. Such codes require time and training to learn a command-line workflow involving multiple input and configuration files, execution on a high-performance server or cluster, post-processing with specialized software and finally visualization. Such workflows are error prone an difficult to reproduce. Cloud computing and UI design are core competencies of RadiaSoft LLC, where the Sirepo* framework is being developed to make state of the art codes available in the browser of any desktop, laptop or tablet. We present our initial successes as real world examples of knowledge exchange (KE) between industry and the research community. This work is leading to broader knowledge exchange throughout the community by facilitating education of students and enabling instantaneous sharing of simulation details between colleagues. Sirepo design objectives include: seamless integration with legacy codes, low barrier to entry for new users, configuration transfer to command line mode, catalog of provenance to aid reproducibility, and simplified collaboration through multimodal sharing. The Sirepo Scientific Gateway** allows users to directly test the software. The combination of intuitive browser-based GUIs and Sirepo’s server-side application container technology enables simplified computational archiving and reproducibility. If embraced by the community, this could become an important asset for the design, commissioning and future upgrade of particle accelerator and X-ray beamline facilities.
* Sirepo cloud computing framework, https://github.com/radiasoft/sirepo
** Sirepo Scientific Gateway, https://sirepo.com

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP046

About •

paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

THPMP047

Advanced Modeling and Optimization of Thermionic Energy Converters

3552

J.P. Edelen, N.M. Cook, C.C. Hall, Y. Hu
RadiaSoft LLC, Boulder, Colorado, USA
J.-L. Vay
LBNL, Berkeley, California, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0017162
Thermionic energy converters (TEC) are a class of thermoelectric devices, which promise improvements to the efficiency and cost of both small- and large-scale electricity generation. A TEC is comprised of a narrowly-separated thermionic emitter and an anode. Simple structures are often space-charge limited as operating temperatures produce currents exceeding the Child-Langmuir limit. We present results from 3D simulations of these devices using the particle-in-cell code Warp, developed at Lawrence Berkeley National Lab. We demonstrate improvements to the Warp code permitting high fidelity simulations of complex device geometries. These improvements include modeling of non-conformal geometries using mesh refinement and cut-cells with a dielectric solver, in addition to importing geometries directly from standard CAD output. In this paper we showcase some of these new features and demonstrate their use.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP047

About •

paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

THPGW073

Status on a Laser Injection in Beam Driven Dielectric Wakefield Accelerator Experiment

3761

G. Andonian, T.J. Campese, F.H. O’Shea
RadiaBeam, Santa Monica, California, USA
D.L. Bruhwiler, N.M. Cook
RadiaSoft LLC, Boulder, Colorado, USA
M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
T. Xu
Northern Illinois University, DeKalb, Illinois, USA

The generation of high-brightness beams with ultra-low emittance using the plasma photocathode technique has gained significant traction in recent years. The practical execution of a combined plasma wakefield acceleration section and a laser injected typically requires a dual gas medium for precision ionization of low and high ionization thresholds. The concept can be partially simplified in experiment by replacing the plasma wakefield acceleration component with a dielectric wakefield acceleration scheme, sacrificing field gradient but maintaining low emittance beam generation. In this paper, we describe the progress on the design of a hybrid scheme, using laser injection in a gas medium within a dielectric wakefield accelerator structure. The proof-of-concept experiment is planned to take place at the Argonne Wakefield Accelerator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW073

About •

paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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