IPAC2019 - List of Authors (Ryne, R.D.)

Paper	Title	Page
WEPTS078	Chaos Indicators for Studying Dynamic Aperture in the IOTA Ring with Protons	3301
	K. Hwang, C.E. Mitchell, R.D. Ryne LBNL, Berkeley, USA
	The Integrable Optics Test Accelerator (IOTA) is a novel storage ring under commissioning at Fermi National Accelerator Laboratory designed (in part) to investigate the dynamics of beams in the presence of highly nonlinear transverse focusing fields that generate integrable single-particle motion. In this study, we explore the sensitivity of the lattice dynamic aperture to the presence of nonlinear space charge. For this purpose, two distinct chaos indicators are compared (frequency map analysis and forward-backward integration). Because the integrability of motion requires integer betatron tune advance between passes through the nonlinear magnetic element, a large role is played by space-charge-induced tune spread. As a result, these tools are also applied to a toy model of the IOTA lattice to investigate the sensitivity of dynamic aperture to violations of the integer tune advance condition.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS078
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPTS083	Multipass Simulations of Space Charge Compensation using Electron Columns at IOTA	3313
	C.S. Park, E.G. Stern Fermilab, Batavia, Illinois, USA S. Chattopadhyay, B.T. Freemire Northern Illinois University, DeKalb, Illinois, USA C.E. Mitchell, R.D. Ryne LBNL, Berkeley, USA
	Defocusing repulsive forces due to self space charge fields lead to degradation of high-intensity particle beams. Being of particular concern for low- and medium-energy proton beams, they result in emittance growth, beam halo formation, and beam loss. They set stringent limits on the intensity of frontier accelerators; therefore, the mitigation of space charge effects is a crucial challenge to improve proton beam intensity. The space charge effects in a positively charged proton beam can be effectively compensated using negatively charged electron columns. In this paper, we present the results of simulations using Synergia of the Electron Column lattice for IOTA. Beam loss due to space charge effects and aperture restrictions have been studied, as well as bunch formation and matching using an adiabatic ramp of the RF cavity. The results show the need for space charge compensation, and provide the basis for integration of the Synergia and Warp codes in order to form a complete simulation of space charge compensation using an Electron Column in IOTA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS083
About •	paper received ※ 16 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

Chaos Indicators for Studying Dynamic Aperture in the IOTA Ring with Protons

3301

K. Hwang, C.E. Mitchell, R.D. Ryne
LBNL, Berkeley, USA

The Integrable Optics Test Accelerator (IOTA) is a novel storage ring under commissioning at Fermi National Accelerator Laboratory designed (in part) to investigate the dynamics of beams in the presence of highly nonlinear transverse focusing fields that generate integrable single-particle motion. In this study, we explore the sensitivity of the lattice dynamic aperture to the presence of nonlinear space charge. For this purpose, two distinct chaos indicators are compared (frequency map analysis and forward-backward integration). Because the integrability of motion requires integer betatron tune advance between passes through the nonlinear magnetic element, a large role is played by space-charge-induced tune spread. As a result, these tools are also applied to a toy model of the IOTA lattice to investigate the sensitivity of dynamic aperture to violations of the integer tune advance condition.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS078

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)

WEPTS083

Multipass Simulations of Space Charge Compensation using Electron Columns at IOTA

3313

C.S. Park, E.G. Stern
Fermilab, Batavia, Illinois, USA
S. Chattopadhyay, B.T. Freemire
Northern Illinois University, DeKalb, Illinois, USA
C.E. Mitchell, R.D. Ryne
LBNL, Berkeley, USA

Defocusing repulsive forces due to self space charge fields lead to degradation of high-intensity particle beams. Being of particular concern for low- and medium-energy proton beams, they result in emittance growth, beam halo formation, and beam loss. They set stringent limits on the intensity of frontier accelerators; therefore, the mitigation of space charge effects is a crucial challenge to improve proton beam intensity. The space charge effects in a positively charged proton beam can be effectively compensated using negatively charged electron columns. In this paper, we present the results of simulations using Synergia of the Electron Column lattice for IOTA. Beam loss due to space charge effects and aperture restrictions have been studied, as well as bunch formation and matching using an adiabatic ramp of the RF cavity. The results show the need for space charge compensation, and provide the basis for integration of the Synergia and Warp codes in order to form a complete simulation of space charge compensation using an Electron Column in IOTA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS083

About •

paper received ※ 16 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)