HB2016 - List of Authors (Chao, A.)

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TUAM1X01

A Two Particle Model for Study of Effects of Space-Charge Force on Strong Head-Tail Instabilities.

Y.H. Chin
KEK, Ibaraki, Japan
M. Blaskiewicz
BNL, Upton, Long Island, New York, USA
A. Chao
SLAC, Menlo Park, California, USA
Y. Shobuda
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In this talk, I present a new two particle model for study of strong head-tail instabilities in the presence of the space-charge force. It is a simple expansion of the well-known two particle model. No chromaticity effect is included. It leads to a formula for the growth rate as a function of the two dimensionless parameters: the space-charge tune shift parameter (normalized by the synchrotron tune) and the wake field strength, Υ. The 3-dimensional contour plot of the growth rate as a function of those two dimensionless parameters reveals stopband structures. Many simulation results generally indicate that a strong head-tail instability can be damped by a weak space-charge force, but the beam becomes unstable again when the space-charge force is further increased. The new two particle model indicates a similar behavior. In weak space-charge regions, additional tune shifts by the space-charge force dissolve the mode-coupling. As the space-charge force is increased, they conversely restore the mode-coupling, but then a further increase of the space-charge force decouples the modes again. This mode coupling/decoupling behavior creates the stopbands structures.

Slides TUAM1X01 [9.082 MB]

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Paper	Title	Page
TUAM1X01	A Two Particle Model for Study of Effects of Space-Charge Force on Strong Head-Tail Instabilities.
	Y.H. Chin KEK, Ibaraki, Japan M. Blaskiewicz BNL, Upton, Long Island, New York, USA A. Chao SLAC, Menlo Park, California, USA Y. Shobuda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In this talk, I present a new two particle model for study of strong head-tail instabilities in the presence of the space-charge force. It is a simple expansion of the well-known two particle model. No chromaticity effect is included. It leads to a formula for the growth rate as a function of the two dimensionless parameters: the space-charge tune shift parameter (normalized by the synchrotron tune) and the wake field strength, Υ. The 3-dimensional contour plot of the growth rate as a function of those two dimensionless parameters reveals stopband structures. Many simulation results generally indicate that a strong head-tail instability can be damped by a weak space-charge force, but the beam becomes unstable again when the space-charge force is further increased. The new two particle model indicates a similar behavior. In weak space-charge regions, additional tune shifts by the space-charge force dissolve the mode-coupling. As the space-charge force is increased, they conversely restore the mode-coupling, but then a further increase of the space-charge force decouples the modes again. This mode coupling/decoupling behavior creates the stopbands structures.
	Slides TUAM1X01 [9.082 MB]
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)