  The evolution of spherical single-mass star clusters driven by two-body
relaxation was followed beyond core collapse by numerically solving the
orbit-averaged Fokker-Planck equation in energy--angular momentum space. The
heating effect by three-body binaries was incorporated in the Fokker-Planck
models. The development of velocity anisotropy after the core collapse is
discussed in detail. The anisotropy in the outer regions continues to increase
slowly after the collapse. In clusters comprising a relatively small number of
stars ($N \ltsim 10000$), the post-collapse expansion is nearly self-similar
and the anisotropy at each of inner Lagrangian radii is nearly constant. In
clusters comprising a larger number of stars ($N \gtsim 10000$), gravothermal
oscillations occur and the anisotropy at each of the inner radii oscillates
with the core oscillations. There is no qualitative difference in the nature of
the gravothermal oscillations between the isotropic and anisotropic
Fokker-Planck models.

Astrophysics