2020/07/31 by Marco Antonelli, B. Haskell, Brynmor Haskell
Physics and Astronomy · #Astrophysics #Classical mechanics #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Mechanics #Neutron star #Physics #Pinning force #Pulsar #Pulsars and Gravitational Waves Research #Quantum, superfluid, helium dynamics #Superconductivity #Superfluidity #Vortex #astro-ph.HE #cond-mat.supr-con
paper · pdf · doi:10.1093/mnras/staa3097
published as MNRAS 499, 3 (2020) 3690-3705 · 18 pages, 11 figures
openalex publication_date 2020/10/07 · arxiv created 2020/11/18 · arxiv updated 2020/11/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT Understanding the average motion of a multitude of superfluid vortices in the interior of a neutron star is a key ingredient for most theories of pulsar glitches. In this paper, we propose a kinetic approach to compute the mutual friction force that is responsible for the momentum exchange between the normal and superfluid components in a neutron star, where the mutual friction is extracted from a suitable average over the motion of many vortex lines. As a first step towards a better modelling of the repinning and depinning processes of many vortex lines in a neutron star, we consider here only straight and non-interacting vortices: we adopt a minimal model for the dynamics of an ensemble of point vortices in two dimensions immersed in a non-homogeneous medium that acts as a pinning landscape. Since the degree of disorder in the inner crust or outer core of a neutron star is unknown, we compare the two possible scenarios of periodic and disordered pinscapes. This approach allows us to extract the mutual friction between the superfluid and the normal component in the star when, in addition to the usual Magnus and drag forces acting on vortex lines, also a pinning force is at work. The effect of disorder on the depinning transition is also discussed.