MEAN-FIELD INSTABILITIES IN DISSIPATIVE HEAVY-ION COLLISIONS

We discuss new reaction mechanisms that may occur in semi-peripheral h eavy ion collisions at intermediate energies. In particular we focus o n the dynamics of the overlapping zone, showing the development of nec k instabilities, coupled with the possibility of an increasing amount of dynamical fluctuations. In a very selected beam energy range betwee n 40 and 70 MeV/u we observe an important interplay between stochastic nucleon exchange and the random nature of nucleon-nucleon collisions. Expected consequences are intermediate mass fragment emissions from t he neck region and large variances in the projectile-like and target-l ike observables. The crucial importance of a time matching between the growth of mean field instabilities and the separation of the interact ing system is stressed. Some hints towards the observation of relative ly large instability effects in deep inelastic collisions at lower ene rgy are finally suggested.