Superconducting Phases in Neutron Star Cores

Using a phenomenological Ginzburg–Landau model that includes entrainment, we identify the possible ground states for neutron and proton condensates in core of star, as function magnetic field strength. Combining analytical numerical techniques, find much outer is likely to be “type-1.5” superconductor (instead type-II often assumed), which flux distributed inhomogeneously, with bundles fluxtubes separated by flux-free Meissner regions. We provide an approximate criterion determine transition between this type-1.5 phase type-I region inner core. also show can coexist non-superconducting regions, but only small part parameter space.