  It is well known that non-central nuclear forces, such as the spin-orbital
coupling and the tensor force, play important roles in understanding many
interesting features of nuclear structures. However, their dynamical effects in
nuclear reactions are poorly known since only the spin-averaged observables are
normally studied both experimentally and theoretically. Realizing that
spin-sensitive observables in nuclear reactions may carry useful information
about the in-medium properties of non-central nuclear interactions, besides
earlier studies using the time-dependent Hartree-Fock approach to understand
effects of spin-orbital coupling on the threshold energy and spin polarization
in fusion reactions, some efforts have been made recently to explore dynamical
effects of non-central nuclear forces in intermediate-energy heavy-ion
collisions using transport models. The focuses of these studies have been on
investigating signatures of the density and isospin dependence of the form
factor in the spin-dependent single-nucleon potential. Interestingly, some
useful probes were identified in the model studies while so far there is still
no data to compare with. In this brief review, we summarize the main physics
motivations as well as the recent progress in understanding the spin dynamics
and identifying spin-sensitive observables in heavy-ion reactions at
intermediate energies. We hope the interesting, important, and new physics
potentials identified in the spin dynamics of heavy-ion collisions will
stimulate more experimental work in this direction.
