Dm. Sedrakian et al., TYPE-I SUPERCONDUCTIVITY OF PROTONS IN NEUTRON-STARS, Monthly Notices of the Royal Astronomical Society, 290(1), 1997, pp. 203-207
The magnetic structure of neutron vortices in the superfluid cores of
neutron stars is determined assuming that the proton condensate forms
a type I superconductor. It is shown that the entrainment currents ind
uced by the neutron vortex circulation cause the proton superconductor
to break into successive domains of normal and superconducting region
s. The Gibbs free-energy is found in the case in which the normal doma
ins form cylindrical tubes coaxial with the neutron vortex. The minimu
m of the energy functional corresponds to a tube radius a similar to 0
.1-0.5b, where b is the outer radius of the neutron vortex. The magnet
ic field within the tube is of the order of 5 x 10(14) G.