Particle dynamics inside a quasi-isochronous storage ring

Journal Article · Sat Feb 01 04:00:00 EST 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.52961· OSTI ID:574606

Ng, K Y ^[1]; Bai, M; Brabson, B; Chu, C M; Kang, X; Jeon, D; Lee, S Y; Riabko, A; Zhao, X ^[2]

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1. Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States)
2. Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States)

Quasi-isochronous {alpha}-like bucket can be important in providing ultra short bunches. The instability of a bunch inside the bucket is found to be severely affected by rf phase modulation. The synchrotron tune drops to zero at the bucket edge very rapidly, indicating the possibility of a thick chaotic layer due to overlapping of resonance islands. The approach to chaos comes from a sequence of bifurcation into 2:1 parametric resonances. When quantum excitation is included in addition to radiation damping, the instability is worsened. The steady-state particle distribution in the longitudinal phase space is Gaussian in the phase coordinate and non-Gaussian in the momentum coordinate, unless the bunch is small. The size of the bunch is governed only by the {open_quotes}thermal Energy{close_quotes} E{sub th}=D{sup 2}/2A, where D and A are, respectively, the normalized diffusion and damping coefficients. The quantum lifetime of the particle bunch, for the D and A that have been enhanced by the smallness of the phase-slip factor, is studied and turns out to be much longer than expected. Phase modulation tends to enhance quantum diffusion at high frequencies, but leads to stochastic resonances instead at low frequencies. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 574606
• Report Number(s): CONF-9609198--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 395; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
BEAM DYNAMICS
ELECTRON BEAMS
FOURIER ANALYSIS
HAMILTONIAN FUNCTION
INSTABILITY
NONLINEAR PROBLEMS
PARTICLE LOSSES
RESONANCE
STOCHASTIC PROCESSES
STORAGE RINGS