 9334 Tennyson , J.L., Meiss , J.D., Morrison , P.J.
 Selfconsistent Chaos in the BeamPlasam Instability
(64K, LaTeX, no figures included)
Feb 15, 93

Abstract ,
Paper (src),
View paper
(auto. generated ps),
Index
of related papers

Abstract. The effect of selfconsistency on Hamiltonian systems with a large number
of degreesoffreedom is investigated for the beamplasma instability using
the singlewave model of O'Neil, Winfrey, and Malmberg. The singlewave
model is reviewed and then rederived within the Hamiltonian context, which
leads naturally to canonical actionangle variables. Simulations are
performed with a large ($10^4$) number of beam particles interacting with
the single wave. It is observed that the system relaxes into a time
asymptotic periodic state where only a few collective degrees are active;
namely, a clump of trapped particles oscillating in a modulated wave,
within a uniform chaotic sea with oscillating phase space boundaries. Thus
selfconsistency is seen to effectively {\sl reduce} the number of
degreesoffreedom. A simple low degreeoffreedom model is derived that
treats the clump as a single {\it macroparticle}, interacting with the wave
and chaotic sea. The uniform chaotic sea is modeled by a fluid waterbag,
where the waterbag boundaries correspond approximately to invariant tori.
This low degreeoffreedom model is seen to compare well with the
simulation.
 Files:
9334.tex