LOCAL AND GLOBAL ORDER IN A SIMULATED 2-DIMENSIONAL LIQUID UNDER STEADY SHEAR

The dependence of ''stringlike'' order on system size in nonequilibriu m molecular dynamics simulations of a two-dimensional liquid of soft d isks under steady shear is reported. Local order, as measured by the c alculated Bragg intensities from a fixed scattering volume, is found t o be independent of the simulation box length. The global ordering of the ''strings,'' however, is observed to decrease steadily with increa sing cell length along the how direction. This is a consequence of the increase in the number of uncorrelated domains as the system becomes larger. The implications of the (probable) disappearance of global ord er in the thermodynamic limit for the discussion concerning choice of thermostat is considered. It is suggested that the domains of shear-in duced order may arise from the large structural fluctuations at equili brium.