Author: Li, R.
Paper Title Page
WEPIK113 Entrance and Exit CSR Impedance for Non-Ultrarelativistic Beam 3214
 
  • R. Li
    JLab, Newport News, Virginia, USA
  • C.-Y. Tsai
    Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
 
  Funding: Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177
For a high-brightness electron beam being transported through beamlines involving bending systems, the coherent synchrotron radiation (CSR) and longitudinal space charge (LSC) interaction could often cause microbunching instability. The semi-analytical Vlasov solver for microbunching gain* depends on the impedances for the relevant collective effects. The existing results for CSR impedances are usually obtained for the ultrarelativistic limit. To extend the microbunching analysis to cases of low energies, such as the case of an ERL merger, or to density modulations at extremely small wavelength, it is necessary to extend the impedance analysis to the non-ultrarelativistic regime. In this study, we present the impedance analysis for the transient CSR interaction in the non-ultrarelativistic regime, for transients including both entrance to and exit from a magnetic dipole. These impedance results will be compared to their ultra-relativistic counterparts**, and the corresponding wakefield obtained from the impedance for low-energy beams will be compared with the existing results of transient CSR wakefield for general beam energies***.
* C.-Y. Tsai et al., Proc. of IPAC'15, 596 (2015).
** C. Mitchell et al ., Proc. of IPAC'13, 1832 (2014).
*** E. L. Saldin et al ., Nucl. Instrum. Meth. A 398, 373 (1997).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK113  
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THPAB080 Estimations of Coherent Instabilities for JLEIC 3903
 
  • R. Li
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177
JLEIC is the medium energy electron-ion collider currently under active design at Jefferson Lab*. The design goals of JLEIC are both high luminosity (1033-1034 cm-2ses−1) and high polarization (>70%) for the electron and light ion beams, for a wide range of electron and ion beam energies and for a wide spectrum of ion species. The unprecedented luminosity goal for this electron-ion collider sets strong requirements for the understanding and management of potential collective effects in JLEIC. In this paper, we present preliminary estimations of single and coupled bunch coherent instabilities for the electron and proton beams at collision energies for the JLEIC design. Further improvement of the estimations and mitigation methods are discussed.
* MEIC design summary, http://arxiv.org/ftp/arxiv/papers/1504/1504.07961.pdf, (2015).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB080  
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