  The discrete kinetic model is used to study the propagation of sound waves in
system of hard-disk-like rotating stars (or vortex gases). The anomalous
(negative) attenuation or amplification which is possibly due to the binary
collision of a dilute-enough rotating disk (or vortex-gas) system (each with
opposite-sign rotating direction or angular momenta but the total (net) angular
momenta or vorticity is zero) or microreversibility might arise from the
implicit balance of the angular momentum during encounter and give clues to the
understanding of possible acceleration of cosmic rays passing through this kind
of channel and direct or inverse vortex-gas cascades in two-dimensional
turbulence of astrophysical problems.
