A biography of the magnetic field of a neutron star

After some post-natal cooling, a spinning, magnetized, canonical neutron-star (NS) has a core of superconducting protons, superfluid neutrons, and degenerate extreme relativistic electrons, all surrounded by a thin highly conducting solid crust. The quantum fluids are threaded by a dense array of quantized vortex-lines which can interact strongly with a denser and much less uniform one of quantized magnetic flux-tubes. The physics of such a core predicts the evolution of a NS's surface magnetic field and related phenomena as the star's spin changes. Predictions include changes in NS magnetic dipole moments, anomalously small polar caps in millisecond pulsars, properties of two different families of spin-period "glitches", and spin-down ages much greater than true ages for some pulsars. Quantitative model-based estimates for all of these are given. None are in conflict with observations.