NAPAC2016 - Classification: 5: Beam Dynamics and EM Fields / D07 - High Intensity Circular Machines

Paper	Title	Page
WEA4CO02	Impact of Space Charge on Beam Dynamics and Integrability in the IOTA Ring
	C.C. Hall, D.L. Bruhwiler, N.M. Cook, R.A. Kishek, S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, 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. Modern hadron accelerators such as spallation sources and neutrino factories must push the intensity limits to meet increasingly challenging goals. The Integrable Optics Test Accelerator (IOTA) is a small ring, currently under construction at Fermilab, which will explore advanced concepts in beam dynamics with low-energy proton beams with high space charge tune depression. Through use of a special nonlinear magnet insertion, large tune spread with amplitude can be achieved while preserving two integrals of motion for the single particle behavior. The tune shift and spread induced by space charge can disrupt the stability of these invariants. In this work we examine the behavior of these invariants in the presence of space charge. Simulations of a modified IOTA lattice that accounts for the space charge tune depression are shown, and the behavior of the invariants is examined.
	Slides WEA4CO02 [0.801 MB]
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WEA4CO03	Intrinsic Landau Damping of Space Charge Modes at Coupling Resonance	863
	A. Macridin, J.F. Amundson, A.V. Burov, P. Spentzouris, E.G. Stern Fermilab, Batavia, Illinois, USA
	Funding: This work was performed at Fermilab, operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Using Synergia accelerator modeling package and Dynamic Mode Decomposition technique, the properties of the first transverse dipole mode in Gaussian bunches with space charge are compared at transverse coupling resonance and off-resonance. The Landau damping at coupling resonance and in the strong space charge regime is a factor of two larger, while the mode's tune and shape are nearly the same. While the damping mechanism in the off-resonance case fits well with the classical Landau damping paradigm, the enhancement at coupling resonance is due to a higher order mode-particle coupling term which is modulated by the amplitude oscillation of the resonance trapped particles.
	Slides WEA4CO03 [3.422 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA4CO03
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WEA4CO04	Suppression of Half-Integer Resonance in FNAL Booster and Space Charge Losses at Injection
	A. Valishev, Y.I. Alexahin, V.A. Lebedev Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact on half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.
	Slides WEA4CO04 [3.828 MB]
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THPOA19	Design Considerations for Proposed Fermilab Integrable RCS	1138
	J.S. Eldred, A. Valishev Fermilab, Batavia, Illinois, USA
	Integrable optics is an innovation in particle accelerator design that provides strong nonlinear focusing while avoiding parametric resonances. One promising application of integrable optics is to overcome the traditional limits on accelerator intensity imposed by betatron tune-spread and collective instabilities. The efficacy of high-intensity integrable accelerators will be undergo comprehensive testing over the next several years at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER). We propose an integrable RCS (iRCS) as a replacement for the Fermilab Booster to achieve multi-MW beam power for the Fermilab high-energy neutrino program. We provide a overview of the machine parameters and discuss an approach to lattice optimization. Integrable optics requires arcs with integer-pi phase advance followed by drifts with matched beta functions. We provide an example integrable lattice with features of a modern RCS - long dispersion-free drifts, low momentum compaction, superperiodicity, chromaticity correction, separate-function magnets, and bounded beta functions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA19
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THPOA23	Adaptive Matching of the IOTA Ring Linear Optics for Space Charge Compensation	1152
	A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA D.L. Bruhwiler, N.M. Cook, C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA
	Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions of linear optics. Many aspects of machine operation depend on proper relations between lattice functions and phase advances, and can be improved with proper treatment of space charge effects. We implement an adaptive algorithm for linear lattice re-matching with full account of space charge in the linear approximation for the case of Fermilab's IOTA ring. The method is based on a search for initial second moments that give closed solution and, at the same time, satisfy predefined set of goals for emittances, beta functions, dispersions and phase advances at and between points of interest. Iterative singular value decomposition based technique is used to search for optimum by varying wide array of model parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA23
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Paper

Title

Page

WEA4CO02

Impact of Space Charge on Beam Dynamics and Integrability in the IOTA Ring

C.C. Hall, D.L. Bruhwiler, N.M. Cook, R.A. Kishek, S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, 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.
Modern hadron accelerators such as spallation sources and neutrino factories must push the intensity limits to meet increasingly challenging goals. The Integrable Optics Test Accelerator (IOTA) is a small ring, currently under construction at Fermilab, which will explore advanced concepts in beam dynamics with low-energy proton beams with high space charge tune depression. Through use of a special nonlinear magnet insertion, large tune spread with amplitude can be achieved while preserving two integrals of motion for the single particle behavior. The tune shift and spread induced by space charge can disrupt the stability of these invariants. In this work we examine the behavior of these invariants in the presence of space charge. Simulations of a modified IOTA lattice that accounts for the space charge tune depression are shown, and the behavior of the invariants is examined.

Slides WEA4CO02 [0.801 MB]

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

WEA4CO03

Intrinsic Landau Damping of Space Charge Modes at Coupling Resonance

863

A. Macridin, J.F. Amundson, A.V. Burov, P. Spentzouris, E.G. Stern
Fermilab, Batavia, Illinois, USA

Funding: This work was performed at Fermilab, operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Using Synergia accelerator modeling package and Dynamic Mode Decomposition technique, the properties of the first transverse dipole mode in Gaussian bunches with space charge are compared at transverse coupling resonance and off-resonance. The Landau damping at coupling resonance and in the strong space charge regime is a factor of two larger, while the mode's tune and shape are nearly the same. While the damping mechanism in the off-resonance case fits well with the classical Landau damping paradigm, the enhancement at coupling resonance is due to a higher order mode-particle coupling term which is modulated by the amplitude oscillation of the resonance trapped particles.

Slides WEA4CO03 [3.422 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA4CO03

Export •

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

WEA4CO04

Suppression of Half-Integer Resonance in FNAL Booster and Space Charge Losses at Injection

A. Valishev, Y.I. Alexahin, V.A. Lebedev
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact on half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.

Slides WEA4CO04 [3.828 MB]

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THPOA19

Design Considerations for Proposed Fermilab Integrable RCS

1138

J.S. Eldred, A. Valishev
Fermilab, Batavia, Illinois, USA

Integrable optics is an innovation in particle accelerator design that provides strong nonlinear focusing while avoiding parametric resonances. One promising application of integrable optics is to overcome the traditional limits on accelerator intensity imposed by betatron tune-spread and collective instabilities. The efficacy of high-intensity integrable accelerators will be undergo comprehensive testing over the next several years at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER). We propose an integrable RCS (iRCS) as a replacement for the Fermilab Booster to achieve multi-MW beam power for the Fermilab high-energy neutrino program. We provide a overview of the machine parameters and discuss an approach to lattice optimization. Integrable optics requires arcs with integer-pi phase advance followed by drifts with matched beta functions. We provide an example integrable lattice with features of a modern RCS - long dispersion-free drifts, low momentum compaction, superperiodicity, chromaticity correction, separate-function magnets, and bounded beta functions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA19

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

THPOA23

Adaptive Matching of the IOTA Ring Linear Optics for Space Charge Compensation

1152

A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA
D.L. Bruhwiler, N.M. Cook, C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA

Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions of linear optics. Many aspects of machine operation depend on proper relations between lattice functions and phase advances, and can be improved with proper treatment of space charge effects. We implement an adaptive algorithm for linear lattice re-matching with full account of space charge in the linear approximation for the case of Fermilab's IOTA ring. The method is based on a search for initial second moments that give closed solution and, at the same time, satisfy predefined set of goals for emittances, beta functions, dispersions and phase advances at and between points of interest. Iterative singular value decomposition based technique is used to search for optimum by varying wide array of model parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA23

Export •

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