We discuss fragmentation mechanisms and isospin transport occurring in
central collisions between neutron rich systems at Fermi energies. In
particular, isospin effects are analyzed looking at the correlations between
fragment isotopic content and kinematical properties. Simulations are based on
an approximate solution of the Boltzmann-Langevin (BL) equation. An attempt to
solve the complete BL equation, by introducing full fluctuations in phase space
is also discussed.Comment: 10 pages, 4 figures; Int.Nucl.Phys.Conf., Tokyo June 07, to appear in
Nucl.Phys.A (Elsart