Nuclear fluid dynamics for giant resonances

Abstract

Nuclear fluid dynamics is an attempt to understand nuclear collective motion in terms of one local macroscopic velocity field common to alt nucleons of a given type. Based on a generalized scaling assumption for the single-particle density matrix it incorporates dynamical distortions of the local Fermi surface. Sound propagation may thus be considered as an approximation to Landau's zero sound modes in Fermi fluids. For finite spherical nuclei the resulting differential equations are solved for isoscalar and isovector modes of different spin-parities. Boundary conditions allow for bound discrete solutions and for unbound modes embedded in the particle continuum. Excitation energies and their dependence on particle number A and on Landau parameters, transition densities, flow patterns of transition currents and B-values are obtained. For unbound solutions strengthfunctions for the excitation with external fields may be calculated.