IPAC2018 - List of Authors (Kuroo, N.)

Paper	Title	Page
THPAF089	Mode Coupling Theory in Collisions With a Large Crossing Angle	3197
	N. Kuroo UTTAC, Tsukuba, Ibaraki, Japan K. Hirosawa, K. Ohmi, D. Zhou KEK, Ibaraki, Japan K. Oide, F. Zimmermann CERN, Geneva, Switzerland
	We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. Cross wake force is introduced to represent the head-tail correlation between colliding beams. The cross wake force is localized at the collision point. Mode coupling theory based on the cross wake force is developed. Collision scheme with a large crossing angle is being very popular in design of electron positron collider. In SuperKEKB project, a collision with a large crossing angle is performed to boost the luminosity ~ 10³⁶ cm^-2s⁻¹. Future circular collider, FCC is also designed with a large crossing angle. Strong-strong simulations have shown a strong coherent head-tail instability, which can limit the performance of proposed future colliders. The mode coupling theory using the cross wake force explains the instability. The instability may affect all colliders designs based on the crab waist scheme.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF089
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THPAK099	The Influence of Higher Order Multipoles of IR Magnets on Luminosity for SuperKEKB	3463
SUSPF061	use link to see paper's listing under its alternate paper code
	K. Hirosawa, T. Okada Sokendai, Ibaraki, Japan N. Kuroo UTTAC, Tsukuba, Ibaraki, Japan K. Ohmi, N. Ohuchi, D. Zhou KEK, Ibaraki, Japan
	SuperKEKB is an electron-positron circular collider upgraded from KEKB. To reach higher luminosity, values of beta are extremely small at Interaction Point. Although magnets in interaction region have a very strong focusing effect, they make a large disturbance to beams. Higher order multipoles and their skew components of magnetic fields of IR magnets are located at a very high beta section with pi/2 phase difference from IP. These multipoles can give critical effect to beam dynamics at interaction point and reduce luminosity on SuperKEKB design. In this study, we calculated beam dynamics for effect of skew components for multipole magnet, and estimated the influence on luminosity by them.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK099
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Mode Coupling Theory in Collisions With a Large Crossing Angle

3197

N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
K. Hirosawa, K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
K. Oide, F. Zimmermann
CERN, Geneva, Switzerland

We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. Cross wake force is introduced to represent the head-tail correlation between colliding beams. The cross wake force is localized at the collision point. Mode coupling theory based on the cross wake force is developed. Collision scheme with a large crossing angle is being very popular in design of electron positron collider. In SuperKEKB project, a collision with a large crossing angle is performed to boost the luminosity ~ 10³⁶ cm^-2s⁻¹. Future circular collider, FCC is also designed with a large crossing angle. Strong-strong simulations have shown a strong coherent head-tail instability, which can limit the performance of proposed future colliders. The mode coupling theory using the cross wake force explains the instability. The instability may affect all colliders designs based on the crab waist scheme.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF089

Export •

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

THPAK099

The Influence of Higher Order Multipoles of IR Magnets on Luminosity for SuperKEKB

3463

SUSPF061

use link to see paper's listing under its alternate paper code

K. Hirosawa, T. Okada
Sokendai, Ibaraki, Japan
N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
K. Ohmi, N. Ohuchi, D. Zhou
KEK, Ibaraki, Japan

SuperKEKB is an electron-positron circular collider upgraded from KEKB. To reach higher luminosity, values of beta are extremely small at Interaction Point. Although magnets in interaction region have a very strong focusing effect, they make a large disturbance to beams. Higher order multipoles and their skew components of magnetic fields of IR magnets are located at a very high beta section with pi/2 phase difference from IP. These multipoles can give critical effect to beam dynamics at interaction point and reduce luminosity on SuperKEKB design. In this study, we calculated beam dynamics for effect of skew components for multipole magnet, and estimated the influence on luminosity by them.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK099

Export •

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