Accession Number : ADA135984

Title :   Nonlinear Orbits in Free-Electron Lasers with a Linear Magnetic Wiggler and a Strong Axial Magnetic Guide Field,

Corporate Author : SCIENCE APPLICATIONS INC BOULDER CO PLASMA RESEARCH INST

Personal Author(s) : Hafizi,B ; Aamodt,R E

PDF Url : ADA135984

Report Date : Oct 1983

Pagination or Media Count : 42

Abstract : Single particle trajectories in a free electron laser device consisting of a linear periodic wiggler superimposed on a strong uniform axial guide field are examined by a formalism suitable for perturbation analysis and adaptable to wigglers of arbitrary geometry. For motion locked on to a single resonance (between the gyromotion and the periodicity induced by the wiggler in the axial velocity) and for sufficiently weak wiggler fields, bounded oscillations of the gyroradius and axial velocity are possible for a limited region of parameter and phase space. Optimal parameters for which the largest fraction of particles entering the drift chamber experience limited excursions in gyroradius and in axial velocity are determined. The mean drift of the guiding center off axis is used to determine the allowable length of the wiggler and of the drift tube for beam propagation. With increasing wiggler field bounded motion is eliminated, leading to transition between resonances, chaotic motion and significant spread in axial velocities of electrons. Comparison with experimental results is presented. (Author)

Descriptors :   *Particle trajectories, *Lasers, Orbits, Nonlinear systems, Stochastic processes, Perturbations, Magnetic fields, Space charge, Parameters, Oscillation, Equations of motion

Subject Categories : Lasers and Masers
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE