ACCURACY OF THE VLASOV-NORDHEIM APPROXIMATION IN THE CLASSICAL LIMIT

We report results of studies of heavy-ion collisions in the classical limit. These studies are carried out with two different nucleon-nucleon interaction models. Both models give the empirical energy and density of nuclear matter; however, the compressibility is 250 MeV for one and 535 MeV for the other. Exact simulations of La+La and Au+Au collisions at 50 to 600 MeV/nucleon laboratory energies indicate that these models are not totally unrealistic and may be pedagogically useful. The results also indicate that collisions at Elab400 MeV/nucleon are more sensitive to the interaction model. The models are then used to study the accuracy of the Vlasov-Nordheim approximation in the classical limit by comparing its results for equal mass (A=50) collisions with the exact results at Elab450 MeV/nucleon. We find that it is a reasonable approximation and it reproduces most of the observed effects when the known equation of state (EOS) and collision cross sections (eff) are used. However, it appears difficult to determine both the EOS and eff by fitting the exact results with VN simulations. © 1990 The American Physical Society.