The damping of transverse coherent instabilities by harmonic cavities
(2015) 6th International Particle Accelerator Conference, IPAC 2015 p.102-105- Abstract
At nonzero chromaticity, the threshold current due to transverse coupled bunch instabilities in an electron storage ring is defined by intrabunch head-tail motion of higher than zeroth order. Multibunch tracking simulations predict that this threshold can be increased to several times its original value through the introduction of bunch lengthening harmonic cavities. One previously suggested explanation is the narrower spectra of the elongated bunches but reliable estimates for the threshold currents are not obtainable for anything other than rigid beam motion since the usual Sacherer formalism is not directly applicable to beams in a non-harmonic potential. A new scheme has been developed in which the decay time of a higher than zeroth... (More)
At nonzero chromaticity, the threshold current due to transverse coupled bunch instabilities in an electron storage ring is defined by intrabunch head-tail motion of higher than zeroth order. Multibunch tracking simulations predict that this threshold can be increased to several times its original value through the introduction of bunch lengthening harmonic cavities. One previously suggested explanation is the narrower spectra of the elongated bunches but reliable estimates for the threshold currents are not obtainable for anything other than rigid beam motion since the usual Sacherer formalism is not directly applicable to beams in a non-harmonic potential. A new scheme has been developed in which the decay time of a higher than zeroth order transverse head-tail mode may be estimated by taking into account the synchrotron tune spread generated by the harmonic cavity potential. This scheme is presented along with the results of numerical simulations performed in order to confirm the analytical predictions and justify the assumptions made. The extension of the scheme to more complex scenarios is also discussed.
(Less)
- author
- Cullinan, F. J. ; Nagaoka, Ryutaro ; Skripka, G. LU and Fernandes Tavares, Pedro LU
- organization
- publishing date
- 2015
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- host publication
- 6th International Particle Accelerator Conference, IPAC 2015
- pages
- 4 pages
- publisher
- JACoW Publishing
- conference name
- 6th International Particle Accelerator Conference, IPAC 2015
- conference location
- Richmond, United States
- conference dates
- 2015-05-03 - 2015-05-08
- external identifiers
-
- scopus:84994608041
- ISBN
- 9783954501687
- language
- English
- LU publication?
- yes
- id
- 1a6f1859-edd5-457f-9fb3-15215f6c9f7f
- date added to LUP
- 2017-02-16 14:38:27
- date last changed
- 2022-01-30 18:04:29
@inproceedings{1a6f1859-edd5-457f-9fb3-15215f6c9f7f,
abstract = {{<p>At nonzero chromaticity, the threshold current due to transverse coupled bunch instabilities in an electron storage ring is defined by intrabunch head-tail motion of higher than zeroth order. Multibunch tracking simulations predict that this threshold can be increased to several times its original value through the introduction of bunch lengthening harmonic cavities. One previously suggested explanation is the narrower spectra of the elongated bunches but reliable estimates for the threshold currents are not obtainable for anything other than rigid beam motion since the usual Sacherer formalism is not directly applicable to beams in a non-harmonic potential. A new scheme has been developed in which the decay time of a higher than zeroth order transverse head-tail mode may be estimated by taking into account the synchrotron tune spread generated by the harmonic cavity potential. This scheme is presented along with the results of numerical simulations performed in order to confirm the analytical predictions and justify the assumptions made. The extension of the scheme to more complex scenarios is also discussed.</p>}},
author = {{Cullinan, F. J. and Nagaoka, Ryutaro and Skripka, G. and Fernandes Tavares, Pedro}},
booktitle = {{6th International Particle Accelerator Conference, IPAC 2015}},
isbn = {{9783954501687}},
language = {{eng}},
pages = {{102--105}},
publisher = {{JACoW Publishing}},
title = {{The damping of transverse coherent instabilities by harmonic cavities}},
year = {{2015}},
}