  If a magnetar interior $B$-field exceeds $10^{15}$~G, it will unpair the
proton superconductor in the stellar core by inducing diamagnetic currents that
destroy the Cooper pair coherence. Then, the $P$-wave neutron superfluid in
these non-superconducting regions will couple to the stellar plasma by
scattering of protons off the quasiparticles that are confined in the cores of
neutron vortices by the strong (nuclear) force. The dynamical timescales
associated with this interaction span from several minutes at the crust-core
interface to a few seconds in the deep core. We show that (a) the rapid
crust-core coupling is incompatible with oscillation models of magnetars that
completely decouple the core superfluid from the crust and (b) magnetar
precession is damped by the coupling of normal fluids to the superfluid core
and, if observed, needs to be forced or continuously excited by seismic
activity.

High Energy Astrophysical Phenomena