Superfluid fission dynamics with microscopic approaches

Recent progresses in the description of the latter stage of nuclear fission are reported. Dynamical effects during the descent of the potential towards scission and in the formation of the fission fragments are studied with the time-dependent Hartree-Fock approach with dynamical pairing correlations at the BCS level. In particular, this approach is used to compute the final kinetic energy of the fission fragments. Comparison with experimental data on the fission of ²⁵⁸Fm are made. It is shown that the spherical magic gaps in compact symmetric modes leading to tin fragments are formed well before scission, indicating a pre-formation of the fragments. It is also shown that at least part of the internal excitation energy is stored into low-lying collective vibrations, while, as in fusion, the dynamics is less coupled to high energy modes