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Title: Study of the OCS6 Lattice Using Frequency Maps

Abstract

Frequency maps are employed to study the baseline dampingring lattice. The study is aimed at understanding the reduced dynamicaperture in the lattice with four short straight sections compared to theone with eight short straight sections. Measures to increase the dynamicaperture based on results of this study are suggested.

Authors:
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. Office of AdvancedScientific Computing Research. Office of High Energy Physics
OSTI Identifier:
902149
Report Number(s):
LBNL-62173
R&D Project: Z345CP; BnR: KA1502010; TRN: US0702891
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43; LINEAR COLLIDERS; FREQUENCY DEPENDENCE; BEAM DYNAMICS; APERTURES; DAMPING; ILC damping rings frequency maps dynamic aperture

Citation Formats

Reichel, Ina. Study of the OCS6 Lattice Using Frequency Maps. United States: N. p., 2007. Web. doi:10.2172/902149.
Reichel, Ina. Study of the OCS6 Lattice Using Frequency Maps. United States. doi:10.2172/902149.
Reichel, Ina. Tue . "Study of the OCS6 Lattice Using Frequency Maps". United States. doi:10.2172/902149. https://www.osti.gov/servlets/purl/902149.
@article{osti_902149,
title = {Study of the OCS6 Lattice Using Frequency Maps},
author = {Reichel, Ina},
abstractNote = {Frequency maps are employed to study the baseline dampingring lattice. The study is aimed at understanding the reduced dynamicaperture in the lattice with four short straight sections compared to theone with eight short straight sections. Measures to increase the dynamicaperture based on results of this study are suggested.},
doi = {10.2172/902149},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 02 00:00:00 EST 2007},
month = {Tue Jan 02 00:00:00 EST 2007}
}

Technical Report:

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  • The authors have developed 6-dimensional phase-space code that tracks macroparticles for the study of coherent bunch instabilities and related feedback systems. The model is based on power-series maps to represent the lattice, and allows for straightforward inclusion of effects such as amplitude dependent tune shift, chromaticity, synchrotron oscillations, and synchrotron radiation. It simulates long range wake fields such as resistive-wall effects as well as the higher order modes in cavities. The model has served to study the dynamics relevant to the transverse feedback system currently being commissioned for the Advanced Light Source (ALS). Current work integrates earlier versions into amore » modular system that includes models for transverse and longitudinal feedback systems. It is designed to provide a modular approach to the dynamics and diagnostics, allowing a user to modify the model of a storage ring at run-time without recompilation.« less
  • A new and efficient direct numerical method with second-order convergence accuracy was developed for fully resolved simulations of incompressible viscous flows laden with rigid particles. The method combines the state-of-the-art immersed boundary method (IBM), the multi-direct forcing method, and the lattice Boltzmann method (LBM). First, the multi-direct forcing method is adopted in the improved IBM to better approximate the no-slip/no-penetration (ns/np) condition on the surface of particles. Second, a slight retraction of the Lagrangian grid from the surface towards the interior of particles with a fraction of the Eulerian grid spacing helps increase the convergence accuracy of the method. Anmore » over-relaxation technique in the procedure of multi-direct forcing method and the classical fourth order Runge-Kutta scheme in the coupled fluid-particle interaction were applied. The use of the classical fourth order Runge-Kutta scheme helps the overall IB-LBM achieve the second order accuracy and provides more accurate predictions of the translational and rotational motion of particles. The preexistent code with the first-order convergence rate is updated so that the updated new code can resolve the translational and rotational motion of particles with the second-order convergence rate. The updated code has been validated with several benchmark applications. The efficiency of IBM and thus the efficiency of IB-LBM were improved by reducing the number of the Lagragian markers on particles by using a new formula for the number of Lagrangian markers on particle surfaces. The immersed boundary-lattice Boltzmann method (IBLBM) has been shown to predict correctly the angular velocity of a particle. Prior to examining drag force exerted on a cluster of particles, the updated IB-LBM code along with the new formula for the number of Lagrangian markers has been further validated by solving several theoretical problems. Moreover, the unsteadiness of the drag force is examined when a fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.« less