  Simulations of dusty plasmas were performed using GRAPE-6, a special-purpose
computer designed for gravitational N-body problems. The collective behaviour
of dust particles, which are injected into the plasma, was studied by means of
three-dimensional computer simulations. As an example of a dusty plasma
simulation, we have calculated movement of dust particles in plasmas under
microgravity conditions. In this simulation, a dust-free region called the
"void" is observed in the dust cloud. Another example was to simulate
experiments on Coulomb crystals in plasmas. Formation of a Coulomb crystal was
observed under typical laboratory conditions. For the simulation of a dusty
plasma in microgravity with 3x10^4 particles, GRAPE-6 can perform the whole
operation 1000 times faster than by using a Pentium4-1.6GHz CPU.
