F. J. Cullinan, Å. Andersson, J. Breunlin, M. Brosi, P. F. Tavares
{"title":"Experimental observation of a mode-1 instability driven by Landau cavities in a storage ring","authors":"F. J. Cullinan, Å. Andersson, J. Breunlin, M. Brosi, P. F. Tavares","doi":"10.1103/physrevaccelbeams.27.044403","DOIUrl":null,"url":null,"abstract":"Landau cavities used to lengthen the bunches in storage rings necessarily constitute a significant impedance. Because of the particular phase of the field required for bunch lengthening, they are often detuned quite considerably from resonance, more so than the main cavities. As a result, their impedance can excite the first coupled-bunch mode such that it becomes unstable. This phenomenon has previously been predicted [M. Venturini, <span>Phys. Rev. Accel. Beams</span> <b>21</b>, 114404 (2018)] and characterized in simulations [T. He, <span>Phys. Rev. Accel. Beams</span> <b>25</b>, 024401 (2022)] but experimental observation is yet to be documented. In this paper, the experimental observation of coupled-bunch modes-<math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>±</mo><mn>1</mn></math> excited by the Landau and main cavities in a fourth-generation light-source storage ring is presented. Features of the instability such as amplitude and coherent frequency at saturation have been measured and its dependency on the main rf voltage has been explored. The impact of a parked main cavity has also been investigated.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"20 1","pages":""},"PeriodicalIF":1.5000,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Review Accelerators and Beams","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1103/physrevaccelbeams.27.044403","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
Landau cavities used to lengthen the bunches in storage rings necessarily constitute a significant impedance. Because of the particular phase of the field required for bunch lengthening, they are often detuned quite considerably from resonance, more so than the main cavities. As a result, their impedance can excite the first coupled-bunch mode such that it becomes unstable. This phenomenon has previously been predicted [M. Venturini, Phys. Rev. Accel. Beams21, 114404 (2018)] and characterized in simulations [T. He, Phys. Rev. Accel. Beams25, 024401 (2022)] but experimental observation is yet to be documented. In this paper, the experimental observation of coupled-bunch modes- excited by the Landau and main cavities in a fourth-generation light-source storage ring is presented. Features of the instability such as amplitude and coherent frequency at saturation have been measured and its dependency on the main rf voltage has been explored. The impact of a parked main cavity has also been investigated.
期刊介绍:
Physical Review Special Topics - Accelerators and Beams (PRST-AB) is a peer-reviewed, purely electronic journal, distributed without charge to readers and funded by sponsors from national and international laboratories and other partners. The articles are published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License.
It covers the full range of accelerator science and technology; subsystem and component technologies; beam dynamics; accelerator applications; and design, operation, and improvement of accelerators used in science and industry. This includes accelerators for high-energy and nuclear physics, synchrotron-radiation production, spallation neutron sources, medical therapy, and intense-beam applications.