HB2012 - List of Authors (Hofmann, I.)

Paper

Title

Page

Challenges in Benchmarking of Simulation Codes against Real High Intensity Accelerators

30

I. Hofmann
GSI, Darmstadt, Germany

Benchmarking of simulation codes for linear or circular accelerators involves several levels of complexity, which will be revisited and discussed in this talk. As ultimate goal of benchmarking it is hoped that a predictive capacity and a practical control over emittance growth and/or beam loss can be obtained. We first give some examples of how simulation codes can be used to gain as much understanding of the underlying physics mechanisms as possible, which is an almost inevitable first step. With more and more experimental data from running high intensity accelerators having become available in recent years more questions need to be raised: Besides the proper physics, can we feed our codes with an accurate enough model of the real machine? What actually is the required accuracy, and does a specific accelerator have enough diagnostics to enable this accuracy? In the paper we explore these questions by discussing several examples of benchmarking efforts, their achievements as well as the limits and difficulties that have been encountered.

Slides MOI1C02 [2.838 MB]

TUO3A01

Dynamical Aspects of Emittance Coupling in Intense Beams

240

I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
HIJ, Jena, Germany

In this paper we study in an idealized lattice model the dynamical behavior of non-equipartitioned beams and of approach to equipartition. It is shown that emittance transfer depends on times scales of tune change, but also the direction of crossing the stopbands of space charge resonances. This provides additional information to support the stability charts suggested previously as design tool for high current linacs.

Slides TUO3A01 [4.897 MB]

THO1D01

Fully 3D Long-term Simulation of the Coupling Resonance Experiments at the CERN PS

J. Qiang, R.D. Ryne
LBNL, Berkeley, California, USA
G. Franchetti, I. Hofmann
GSI, Darmstadt, Germany
E. Métral
CERN, Geneva, Switzerland

Funding: This work is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Space-charge driven nonlinear coupling resonance can have significant impact in high intensity linac and ring operation. Such a resonance causes emittance exchange between different degrees of freedom and may result in potential particle loss from the direction with smaller aperture size. In this paper, we will report on numerical simulation studies of the resonance crossing phenomena using a previous experiment at the CERN PS including detailed three-dimensional space-charge effects and machine nonlinearity.

Slides THO1D01 [0.589 MB]

TUO3A01

Dynamical Aspects of Emittance Coupling in Intense Beams

240

I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
HIJ, Jena, Germany

In this paper we study in an idealized lattice model the dynamical behavior of non-equipartitioned beams and of approach to equipartition. It is shown that emittance transfer depends on times scales of tune change, but also the direction of crossing the stopbands of space charge resonances. This provides additional information to support the stability charts suggested previously as design tool for high current linacs.

Slides TUO3A01 [4.897 MB]

Paper	Title	Page
MOI1C02	Challenges in Benchmarking of Simulation Codes against Real High Intensity Accelerators	30
	I. Hofmann GSI, Darmstadt, Germany
	Benchmarking of simulation codes for linear or circular accelerators involves several levels of complexity, which will be revisited and discussed in this talk. As ultimate goal of benchmarking it is hoped that a predictive capacity and a practical control over emittance growth and/or beam loss can be obtained. We first give some examples of how simulation codes can be used to gain as much understanding of the underlying physics mechanisms as possible, which is an almost inevitable first step. With more and more experimental data from running high intensity accelerators having become available in recent years more questions need to be raised: Besides the proper physics, can we feed our codes with an accurate enough model of the real machine? What actually is the required accuracy, and does a specific accelerator have enough diagnostics to enable this accuracy? In the paper we explore these questions by discussing several examples of benchmarking efforts, their achievements as well as the limits and difficulties that have been encountered.
	Slides MOI1C02 [2.838 MB]

TUO3A01	Dynamical Aspects of Emittance Coupling in Intense Beams	240
	I. Hofmann GSI, Darmstadt, Germany I. Hofmann HIJ, Jena, Germany
	In this paper we study in an idealized lattice model the dynamical behavior of non-equipartitioned beams and of approach to equipartition. It is shown that emittance transfer depends on times scales of tune change, but also the direction of crossing the stopbands of space charge resonances. This provides additional information to support the stability charts suggested previously as design tool for high current linacs.
	Slides TUO3A01 [4.897 MB]

THO1D01	Fully 3D Long-term Simulation of the Coupling Resonance Experiments at the CERN PS
	J. Qiang, R.D. Ryne LBNL, Berkeley, California, USA G. Franchetti, I. Hofmann GSI, Darmstadt, Germany E. Métral CERN, Geneva, Switzerland
	Funding: This work is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Space-charge driven nonlinear coupling resonance can have significant impact in high intensity linac and ring operation. Such a resonance causes emittance exchange between different degrees of freedom and may result in potential particle loss from the direction with smaller aperture size. In this paper, we will report on numerical simulation studies of the resonance crossing phenomena using a previous experiment at the CERN PS including detailed three-dimensional space-charge effects and machine nonlinearity.
	Slides THO1D01 [0.589 MB]

TUO3A01	Dynamical Aspects of Emittance Coupling in Intense Beams	240
	I. Hofmann GSI, Darmstadt, Germany I. Hofmann HIJ, Jena, Germany
	In this paper we study in an idealized lattice model the dynamical behavior of non-equipartitioned beams and of approach to equipartition. It is shown that emittance transfer depends on times scales of tune change, but also the direction of crossing the stopbands of space charge resonances. This provides additional information to support the stability charts suggested previously as design tool for high current linacs.
	Slides TUO3A01 [4.897 MB]