R. A. Kishek, P. G. O'Shea, M. Reiser (Institute for Plasma Research, U. Maryland, College Park, 20742)
A universal process of energy transfer is demonstrated in non-equilibrium charged particle beams with anisotropy and space charge. Equipartitioning of energy between available degrees of freedom occurs in just a few betatron wavelengths, without halo formation. Collective space charge modes similar to those observed in recent experiments provide the underlying coupling mechanism. The traditional K-V stability analysis is shown not to apply to beams that originate with a large perturbation from equilibrium, as is typical in the laboratory, implying that the process is is difficult to avoid by proper selection of an operating point. Furthermore, the rate of equipartitioning is shown to depend on a single free parameter related space charge content of the final (equipartitioned) beam, and does not depend on the kinetic energy is initially distributed between the two planes.
* Research Supported by the U. S. Dept. of Energy
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