HB2018 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
MOA1PL01	Challenges in Understanding Space Charge Dynamics	space-charge, simulation, emittance, synchrotron	1
	H. Bartosik CERN, Geneva, Switzerland
	Space charge effects in high intensity and high brightness synchrotrons can lead to undesired beam emittance growth, beam halo formation and particle loss. A series of dedicated machine experiments has been performed over the past decade in order to study these effects in the particular regime of long-term beam storage (10⁵-10⁶ turns) as required for certain applications. This paper gives an overview of the present understanding of the underlying beam dynamics mechanisms. In particular it focuses on the space charge induced periodic resonance crossing, which has been identified as the main mechanism causing beam degradation in this regime. The challenges in further progressing with the understanding, the modelling and the mitigation of these space charge effects and the resulting beam degradation are discussed. Furthermore, an outlook for possible future directions of studies is presented.
	Slides MOA1PL01 [22.877 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOA1PL01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUA2WD02	High-Power Beam Operation at J-PARC	operation, simulation, injection, proton	147
	S. Igarashi KEK, Ibaraki, Japan
	The Japan Proton Accelerator Research Complex (J-PARC) is a multipurpose high-power proton accelerator facility, comprising a 400 MeV linac, a 3 GeV rapid cycling synchrotron (RCS) and a 30 GeV main ring synchrotron (MR). RCS is now providing 500 kW beams to the materials and life science experimental facility (MLF) and its beam power will be increased step by step toward the design value of 1 MW. MR has been operated with the beam power of 500 kW at maximum for the long-baseline neutrino oscillation experiment (T2K). An upgrade plan of MR for the beam power of 1.3 MW for the T2K experiment is promoted with a faster cycling scheme.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUA2WD02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP1WA02	Fixed Field Accelerators and Space Charge Modeling	space-charge, focusing, acceleration, synchrotron	158
	A. Adelmann PSI, Villigen PSI, Switzerland C.T. Rogers STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The efforts of the Fixed Field Accelerators FFA (formerly known as FFAG accelerators) community to address the high intensity challenge are reviewed. Starting from analytic estimates and linear models for space charge computation, the current possibilities of precise 3D models for start to end modeling are discussed.
	Slides TUP1WA02 [9.488 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP1WA02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA1WA01	Sum Resonances with Space Charge	space-charge, coherent-effects, experiment, simulation	226
	G. Franchetti GSI, Darmstadt, Germany
	This presentation will discuss the extension of the theory of the sum resonances with space charge.
	Slides WEA1WA01 [5.267 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEA1WA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO024	Resonance Stop-bands Compensation at Booster Ring of HIAF	alignment, injection, betatron, coupling	315
	J. Li, J.C. Yang IMP/CAS, Lanzhou, People's Republic of China
	Booster Ring (BRing) of the new approved High Intensity heavy-ion Accelerator Facility (HIAF) in China is designed to stack 0.3-1.0·10¹¹ number of 238U³⁵⁺ ions by painting injection and deliver over such intensity beam in extraction. However, depressed tune spread caused by space charge effect crosses the low-order resonance stop-bands after bunching the storage beam. To keep a low beam loss during crossing, stop-band compensation scheme is proposed covering the whole process of RF capture and early acceleration.
	Poster WEP2PO024 [1.218 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA1WD01	Experience and Perspective of FFAG Accelerator	acceleration, proton, cavity, focusing	342
	Y. Mori Kyoto University, Research Reactor Institute, Osaka, Japan
	Funding: This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan) This talk is about operational challenge and perspective of Fixed Field Alternating Gradient accelerators, including the recent studies on advanced FFAG for high intensity secondary particles.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP2WB01	Revisiting the Longitudinal 90 Degree Limit for Superconducting Linear Accelerators	space-charge, lattice, emittance, focusing	369
	I. Hofmann GSI, Darmstadt, Germany I. Hofmann TEMF, TU Darmstadt, Darmstadt, Germany
	In the design of high-intensity linear accelerators one of the generally adopted criteria is not to exceed a zero-current phase advance per focusing period of 90 degrees in order to avoid the space charge driven envelope instability, or a coinciding fourth order space charge resonance. Recently it was claimed that in certain structures, predominantly applicable to super-conducting linac lattices - such a constraint is not always necessary in the longitudinal plane (I. Hofmann and O. Boine-Frankenheim, Phys. Rev. Lett. 118, 2017). This applies primarily to such focusing structures, where the transverse focusing period only induces a weak space charge dependent modulation in the longitudinal plane, and a different periodicity is applicable to the longitudinal plane. Hence the longitudinal 90 degree stopband is practically absent, and phase advances significantly above 90 degrees should be possible in such structures, with a corresponding additional design freedom. As a consequence, we suggest that the 90 degree rule should no longer be taken as standard criterion in the longitudinal plane of linac design.
	Slides THP2WB01 [5.179 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THP2WB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP2WB05	Halo Formation of the High Intensity Beams in a Periodic Solenoidal Fields	space-charge, focusing, solenoid, lattice	387
	Y.L. Cheon, M. Chung UNIST, Ulsan, Republic of Korea
	Funding: This research was supported by the National Research Foundation of Korea (Grant No. NRF-2017M1A7A1A02016413). Transport of intense beams over long distances can be restricted by space-charge fields which force the trajectories of charged particles to deviate from the stable regions of propagation. The space-charge fields can be calculated from the density distribution of the beam particles, and Poisson's equation. As the space-charge term is put in the equations of motion, it affects the envelope equations and betatron wave number of a charged particle in the beam. Also, with different initial conditions of the beam particles, there can be perturbations on the matched beam envelopes which can generate a resonant interaction between the beam core and test particles. Unlike for the K-V beam, for nonuniform density beams such as Gaussian beams in the periodic quadrupole or solenoidal focusing fields, there exists higher order terms and non-periodic solutions of beam particle oscillations, which can generate halo regions and chaotic motions during the beam propagation. In this study, we have investigated the higher order resonances and non-periodic solutions of the Gaussian beam in the solenoidal focusing fields to understand halo formation mechanisms of the intense beams.
	Slides THP2WB05 [2.295 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THP2WB05
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOA1PL01

Challenges in Understanding Space Charge Dynamics

space-charge, simulation, emittance, synchrotron

1

H. Bartosik
CERN, Geneva, Switzerland

Space charge effects in high intensity and high brightness synchrotrons can lead to undesired beam emittance growth, beam halo formation and particle loss. A series of dedicated machine experiments has been performed over the past decade in order to study these effects in the particular regime of long-term beam storage (10⁵-10⁶ turns) as required for certain applications. This paper gives an overview of the present understanding of the underlying beam dynamics mechanisms. In particular it focuses on the space charge induced periodic resonance crossing, which has been identified as the main mechanism causing beam degradation in this regime. The challenges in further progressing with the understanding, the modelling and the mitigation of these space charge effects and the resulting beam degradation are discussed. Furthermore, an outlook for possible future directions of studies is presented.

Slides MOA1PL01 [22.877 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOA1PL01

Export •

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

TUA2WD02

High-Power Beam Operation at J-PARC

operation, simulation, injection, proton

147

S. Igarashi
KEK, Ibaraki, Japan

The Japan Proton Accelerator Research Complex (J-PARC) is a multipurpose high-power proton accelerator facility, comprising a 400 MeV linac, a 3 GeV rapid cycling synchrotron (RCS) and a 30 GeV main ring synchrotron (MR). RCS is now providing 500 kW beams to the materials and life science experimental facility (MLF) and its beam power will be increased step by step toward the design value of 1 MW. MR has been operated with the beam power of 500 kW at maximum for the long-baseline neutrino oscillation experiment (T2K). An upgrade plan of MR for the beam power of 1.3 MW for the T2K experiment is promoted with a faster cycling scheme.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUA2WD02

Export •

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

TUP1WA02

Fixed Field Accelerators and Space Charge Modeling

space-charge, focusing, acceleration, synchrotron

158

A. Adelmann
PSI, Villigen PSI, Switzerland
C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The efforts of the Fixed Field Accelerators FFA (formerly known as FFAG accelerators) community to address the high intensity challenge are reviewed. Starting from analytic estimates and linear models for space charge computation, the current possibilities of precise 3D models for start to end modeling are discussed.

Slides TUP1WA02 [9.488 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP1WA02

Export •

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

WEA1WA01

Sum Resonances with Space Charge

space-charge, coherent-effects, experiment, simulation

226

G. Franchetti
GSI, Darmstadt, Germany

This presentation will discuss the extension of the theory of the sum resonances with space charge.

Slides WEA1WA01 [5.267 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEA1WA01

Export •

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

WEP2PO024

Resonance Stop-bands Compensation at Booster Ring of HIAF

alignment, injection, betatron, coupling

315

J. Li, J.C. Yang
IMP/CAS, Lanzhou, People's Republic of China

Booster Ring (BRing) of the new approved High Intensity heavy-ion Accelerator Facility (HIAF) in China is designed to stack 0.3-1.0·10¹¹ number of 238U³⁵⁺ ions by painting injection and deliver over such intensity beam in extraction. However, depressed tune spread caused by space charge effect crosses the low-order resonance stop-bands after bunching the storage beam. To keep a low beam loss during crossing, stop-band compensation scheme is proposed covering the whole process of RF capture and early acceleration.

Poster WEP2PO024 [1.218 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO024

Export •

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

THA1WD01

Experience and Perspective of FFAG Accelerator

acceleration, proton, cavity, focusing

342

Y. Mori
Kyoto University, Research Reactor Institute, Osaka, Japan

Funding: This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan)
This talk is about operational challenge and perspective of Fixed Field Alternating Gradient accelerators, including the recent studies on advanced FFAG for high intensity secondary particles.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD01

Export •

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

THP2WB01

Revisiting the Longitudinal 90 Degree Limit for Superconducting Linear Accelerators

space-charge, lattice, emittance, focusing

369

I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
TEMF, TU Darmstadt, Darmstadt, Germany

In the design of high-intensity linear accelerators one of the generally adopted criteria is not to exceed a zero-current phase advance per focusing period of 90 degrees in order to avoid the space charge driven envelope instability, or a coinciding fourth order space charge resonance. Recently it was claimed that in certain structures, predominantly applicable to super-conducting linac lattices - such a constraint is not always necessary in the longitudinal plane (I. Hofmann and O. Boine-Frankenheim, Phys. Rev. Lett. 118, 2017). This applies primarily to such focusing structures, where the transverse focusing period only induces a weak space charge dependent modulation in the longitudinal plane, and a different periodicity is applicable to the longitudinal plane. Hence the longitudinal 90 degree stopband is practically absent, and phase advances significantly above 90 degrees should be possible in such structures, with a corresponding additional design freedom. As a consequence, we suggest that the 90 degree rule should no longer be taken as standard criterion in the longitudinal plane of linac design.

Slides THP2WB01 [5.179 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THP2WB01

Export •

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

THP2WB05

Halo Formation of the High Intensity Beams in a Periodic Solenoidal Fields

space-charge, focusing, solenoid, lattice

387

Y.L. Cheon, M. Chung
UNIST, Ulsan, Republic of Korea

Funding: This research was supported by the National Research Foundation of Korea (Grant No. NRF-2017M1A7A1A02016413).
Transport of intense beams over long distances can be restricted by space-charge fields which force the trajectories of charged particles to deviate from the stable regions of propagation. The space-charge fields can be calculated from the density distribution of the beam particles, and Poisson's equation. As the space-charge term is put in the equations of motion, it affects the envelope equations and betatron wave number of a charged particle in the beam. Also, with different initial conditions of the beam particles, there can be perturbations on the matched beam envelopes which can generate a resonant interaction between the beam core and test particles. Unlike for the K-V beam, for nonuniform density beams such as Gaussian beams in the periodic quadrupole or solenoidal focusing fields, there exists higher order terms and non-periodic solutions of beam particle oscillations, which can generate halo regions and chaotic motions during the beam propagation. In this study, we have investigated the higher order resonances and non-periodic solutions of the Gaussian beam in the solenoidal focusing fields to understand halo formation mechanisms of the intense beams.

Slides THP2WB05 [2.295 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THP2WB05

Export •

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