Speaker
Description
Neutron stars glitches, sudden spin-up events observed in their rotation, can be attributed to a transfer of angular momentum from an internal superfluid reservoir through a superfluid vortex-avalanche process. This research extends existing models by introducing new hypotheses in order to achieve a self-consistent description of superfluid vortex dynamics and avalanche probability. Specifically, the effects of vortex inertial mass were analyzed alongside the introduction of a Gaussian shape for the potential describing the interaction of vortices with pinning centers in the stellar crust. A self-consistent velocity- and position-dependent drag parameter was employed to account for dissipative forces.
Results indicate that, while the introduction of inertial mass has a negligible impact under realistic neutron star crust parameters, the Gaussian reshaping of the potential together with the definition of the drag highly affects the dynamics. A statistical approach based on the evaluation of the vortex mean free path provided a time-dependent description of the vortex-avalanches probability, yielding results aligned with observational data. Despite limitations arising from the point-particle description of the vortex and the assumption of a perfectly periodic crystal lattice in the crust, this model provides a robust framework for future developments aimed at incorporating additional physical ingredients to further increase its generality.