SEMICLASSICAL DESCRIPTION OF THE NEUTRON SUPERFLUID IN THE INNER CRUST OF NEUTRON-STARS

The model of a Wigner-Seitz cell consisting of a nucleus embedded in a sea of neutrons is examined with particular attention to the pairing properties of the superfluid neutron liquid. The model describes micro scopically the status of baryonic matter inside the inner crust of neu tron stars, where it is assumed that neutron-rich nuclei disposed in a Coulomb lattice are permeated by a sea of superfluid neutrons at very low temperature. A semi-classical approach based on the local density approximation is followed in order to describe the non-uniform pairin g gap in the Wigner-Seitz cell, and the Gogny force is used to represe nt the nucleon-nucleon interaction. In the range of physically relevan t densities, we find a neutron pairing gap which is generally larger i n the region of the cell outside the nucleus. This behaviour should ha ve consequences on the physics of neutron stars, like cooling patterns and pinning of vortices in rotating stars.