Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation

Abstract In typical numerical simulations, the space-charge force is calculated by slicing a beam into many longitudinal segments and by solving the two-dimensional Poisson equation in each segment. This method neglects longitudinal leakage of the space-charge force to nearby segments owing to its l...

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Autores principales: Yoshihiro Shobuda, Yong Ho Chin
Formato: article
Lenguaje:EN
Publicado: Nature Portfolio 2018
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Acceso en línea:https://doaj.org/article/af5083b9063347019724fa276082aca4
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spelling oai:doaj.org-article:af5083b9063347019724fa276082aca42021-12-02T11:40:25ZRigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation10.1038/s41598-018-30960-22045-2322https://doaj.org/article/af5083b9063347019724fa276082aca42018-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-30960-2https://doaj.org/toc/2045-2322Abstract In typical numerical simulations, the space-charge force is calculated by slicing a beam into many longitudinal segments and by solving the two-dimensional Poisson equation in each segment. This method neglects longitudinal leakage of the space-charge force to nearby segments owing to its longitudinal spread over 1/γ. By contrast, the space-charge impedance, which is the Fourier transform of the wake function, is typically calculated directly in the frequency-domain. So long as we follow these approaches, the longitudinal leakage effect of the wake function will remain to be unclear. In the present report, the space-charge wake function is calculated directly in the time domain by solving the three-dimensional Poisson equation for a longitudinally Gaussian beam. We find that the leakage effect is insignificant for a bunch that is considerably longer than the chamber radius so long as the segment length satisfies a certain condition. We present a criterion for how finely a bunch should be sliced so that the two-dimensional slicing approach can provide a good approximation of the three-dimensional exact solution.Yoshihiro ShobudaYong Ho ChinNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-19 (2018)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Yoshihiro Shobuda
Yong Ho Chin
Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation
description Abstract In typical numerical simulations, the space-charge force is calculated by slicing a beam into many longitudinal segments and by solving the two-dimensional Poisson equation in each segment. This method neglects longitudinal leakage of the space-charge force to nearby segments owing to its longitudinal spread over 1/γ. By contrast, the space-charge impedance, which is the Fourier transform of the wake function, is typically calculated directly in the frequency-domain. So long as we follow these approaches, the longitudinal leakage effect of the wake function will remain to be unclear. In the present report, the space-charge wake function is calculated directly in the time domain by solving the three-dimensional Poisson equation for a longitudinally Gaussian beam. We find that the leakage effect is insignificant for a bunch that is considerably longer than the chamber radius so long as the segment length satisfies a certain condition. We present a criterion for how finely a bunch should be sliced so that the two-dimensional slicing approach can provide a good approximation of the three-dimensional exact solution.
format article
author Yoshihiro Shobuda
Yong Ho Chin
author_facet Yoshihiro Shobuda
Yong Ho Chin
author_sort Yoshihiro Shobuda
title Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation
title_short Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation
title_full Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation
title_fullStr Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation
title_full_unstemmed Rigorous formulation of space-charge wake function and impedance by solving the three-dimensional Poisson equation
title_sort rigorous formulation of space-charge wake function and impedance by solving the three-dimensional poisson equation
publisher Nature Portfolio
publishDate 2018
url https://doaj.org/article/af5083b9063347019724fa276082aca4
work_keys_str_mv AT yoshihiroshobuda rigorousformulationofspacechargewakefunctionandimpedancebysolvingthethreedimensionalpoissonequation
AT yonghochin rigorousformulationofspacechargewakefunctionandimpedancebysolvingthethreedimensionalpoissonequation
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