CRITICAL PERCOLATION IN SYSTEMS OF MOBILE DISKS

Numerical results for critical diffusion in a percolating system of mo ving disks are reported. Critical percolation ensues as the disk densi ty rho approaches the percolation threshold density rho(c) and u --> 0 , where u is a measure of disk speed. Pure percolation behaviour is ob served only for u much less than(rho(c) - rho)(1/q), where q similar o r equal to 0.3. For u much greater than(rho(c) - rho)(1/q), diffusion is dominated by kinetic effects; therein, D similar to u(qu), where D is the diffusion constant and u similar or equal to 1.3.