Disks controlling chaos in a 3D dynamical model for elliptical galaxies
  A 3D dynamical model with a quasi-homogeneous core and a disk component is
used for the chaos control in the central parts of elliptical galaxy. Numerical
experiments in the 2D system show a very complicated phase plane with a large
chaotic sea, considerable sticky layers and a large number of islands, produced
by secondary resonances. When the mass of the disk increases, the chaotic
regions decrease gradually, and, finally, a new phase plane with only regular
orbits appears. This evolution indicates that disks in elliptical galaxies can
act as the chaos controllers. Starting from the results obtained in the 2D
system, we locate the regions in the phase space of the 3D system, producing
regular and chaotic orbits. For this we introduce and use a new dynamical
parameter, the S(w) spectrum, which proves to be useful as a fast indicator and
allows us to distinguish the regular motion from chaos in the 3D potentials.
Other methods for detecting chaos are also discussed.
