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Title: Lower bound on the critical energy for the onset of chaos and the chaotic dynamical aperture of large accelerators

Journal Article · · Physical Review A. General Physics; (United States)
 [1];  [2]
  1. Department of Natural Sciences, Baruch College of The City University of New York, 17 Lexington Avenue, New York 10010 (United States)
  2. Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Conneticut 06511 (United States) Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06511 (United States)

A generic nonintegrable Hamiltonian system is characterized by a critical energy above which chaotic motion sets in. A general method of finding a lower bound to this critical energy that does not require a solution of the equations of motion is discussed. Below the critical energy, the motion is regular everywhere on the energy surface and no instabilities can develop. The method is applied to a practical situation encountered in modern large accelerators, where the transverse motion of the particles in an arrangement of quadrupole, sextupole, and octupole magnetic elements may become chaotic. The chaotic dynamical aperture of the beam is calculated as a function of a dimensionless strength parameter. The estimated critical energy is compared with that obtained from detailed studies of the Poincare sections of the above system at various energies.

DOE Contract Number:
FG02-91ER40608
OSTI ID:
7206196
Journal Information:
Physical Review A. General Physics; (United States), Vol. 45:4; ISSN 1050-2947
Country of Publication:
United States
Language:
English