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 if 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.

The Cause of a Pulsar Glitch

“…• The nucleons in the neutron stars' core form Cooper pairs and exhibit macroscopic quantum behavior [2].…”

“…• The magnetic field in the outer-core is no longer locked to the charged plasma but instead confined to magnetic flux tubes [2].…”

“…• The type of superconductivity in the outer-core depends on the characteristic length scales involved. An estimate of the Ginzburg-Landau parameter for the superconducting protons in the outer-core is given by [2],…”

“…The macroscopic magnetic induction B in the star's core is obtained by summing all individual flux quanta [2].…”