NONLINEAR MEAN-FIELD DYNAMICS IN THE NUCLEAR SPINODAL ZONE

We discuss numerical simulations of mean field dynamics which strongly indicate a chaotic behavior of nuclear matter inside the spinodal reg ion. Spontaneous symmetry-breaking - no explicit fluctuating term is c onsidered - occurs leading to large and unpredictable density fluctuat ions. A proper recipe to calculate an average Lyapunov exponent in thi s multidimensional phase space is introduced. The latter is calculated for different values of the density in order to characterize in a qua ntitative way the chaotic and regular regions. These results strongly suggest that nuclear multifragmentation occurring at intermediate ener gy in heavy-ion reactions could be generated by a chaotic mechanism.