Study of multifragmentation patterns induced by spinodal instabilities

In this article we study the characteristics of multifragmentation patterns induced by spinodal instabilities using a stochastic mean-field approach. For two-dimensional unstable nuclear matter, we find that the early fragmentation process occurs accordingly to few dominant unstable wavelengths. This favours the partition of the system in close-mass pieces, with a lack of very small fragments. Then, we consider the realistic case of spherical systems initialized at low density. The role of finite-size effects, final-state interaction and secondary decay is carefully investigated. We discuss under which conditions some memory of the first dynamical stage survives in the final fragment partitions. (orig.)