Fluxtube dynamics in neutron star cores

Abstract

Although the detailed structure of neutron stars remains unknown, their equilibrium temperatures lie well below the Fermi temperature of dense nuclear matter, suggesting that the nucleons in the stars' core form Cooper pairs and exhibit macroscopic quantum behavior. The presence of such condensates impacts on the neutron stars' large‐scale properties. Specifically, superconducting protons in the outer core (expected to show type‐II properties) alter the stars' magnetism, as the magnetic field is no longer locked to the charged plasma but instead confined to fluxtubes. The motion of these structures governs the dynamics of the core magnetic field. To examine whether field evolution could be driven on observable timescales, several mechanisms affecting the fluxtube distribution are addressed and characteristic timescales for realistic equations of state estimated. The results suggest that the corresponding timescales are not constant but vary for different densities inside the star, generally being shortest close to the crust–core interface.