The infinite length approximation is often used to simplify the calculation of thebeam coupling impedance of accelerator elements. This is expected to be a reasonableassumption for devices whose length is greater than the transverse dimension but may beless accurate approximation for segmented devices. In this contribution we present thestudy of the beam coupling impedance of a finite length device: a cylindrical cavity loadedwith a toroidal slab of lossy dielectric. In order to take into account the finite length,we will decompose the fields in the cavity and in the beam pipe into a set of orthonormalmodes and apply the mode matching method to obtain the impedance. To validate our method,we will present comparisons between analytical formulas and 3D electromagnetic CSTsimulations as well as applications to the evaluation of the impedance of short beam pipeinserts, where the longitudinal and transverse dimensions are difficult to model innumerical simulations. Copyright © 2012 by IEEE.
The mode matching method applied to beam coupling impedance calculations of finitelength devices / Biancacci, Nicolò; E., Metral; B., Salvant; V. G., Vaccaro; Migliorati, Mauro; Palumbo, Luigi. - (2012), pp. 3069-3071. (Intervento presentato al convegno 3rd International Particle Accelerator Conference 2012, IPAC 2012 tenutosi a New Orleans, LA nel 20 May 2012 through 25 May 2012).
The mode matching method applied to beam coupling impedance calculations of finitelength devices
BIANCACCI, NICOLÒ;MIGLIORATI, Mauro;PALUMBO, Luigi
2012
Abstract
The infinite length approximation is often used to simplify the calculation of thebeam coupling impedance of accelerator elements. This is expected to be a reasonableassumption for devices whose length is greater than the transverse dimension but may beless accurate approximation for segmented devices. In this contribution we present thestudy of the beam coupling impedance of a finite length device: a cylindrical cavity loadedwith a toroidal slab of lossy dielectric. In order to take into account the finite length,we will decompose the fields in the cavity and in the beam pipe into a set of orthonormalmodes and apply the mode matching method to obtain the impedance. To validate our method,we will present comparisons between analytical formulas and 3D electromagnetic CSTsimulations as well as applications to the evaluation of the impedance of short beam pipeinserts, where the longitudinal and transverse dimensions are difficult to model innumerical simulations. Copyright © 2012 by IEEE.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
