The star and its interior superfluid begin in co-rotation. The number of superfluid vortices penetrating the inner crust per unit area (blue shading) is highest at the north pole, but diminishes towards the equator owing to the curved stellar surface. A circular crust patch is then rotated (arrows) by plastic deformation, driven by stresses exerted by the twisted magnetic field below the crust If this happens slowly and/or steadily, then its effect on the star's spin-down history might not be obvious.
展开▼
