1307.7020 (S. K. Lander)

The contrasting magnetic fields of superconducting pulsars and magnetars    [PDF]

S. K. Lander

We study equilibrium magnetic field configurations in a neutron star whose core has type-II superconducting protons. Unlike normal matter, whose equations do not involve any special field strength, those for superconductors contain the lower critical field, of order 10^{15} G. We find that the ratio between this critical field and the smooth-averaged stellar magnetic field at the crust-core boundary is the key feature dictating the field geometry. Our results suggest that pulsar and magnetar-strength fields have notably different configurations. Field decay for neutron stars with B_{pole}\sim 10^{14} G could thus result in substantial internal rearrangements, with the toroidal field component being pushed out of the core; this may be related to observed magnetar activity.

View original: http://arxiv.org/abs/1307.7020