Neutron Star Crusts and Alignment of Magnetic Axes in Pulsars

The electromagnetic torque which brakes the rotation of a magnetic neutron star also tends to align the magnetic axis with the rotation axis. For fluid stars the time scale for alignment is comparable to the time scale for rotational braking. However, the presence of a crystalline mantle impedes the alignment of the magnetic axis with the rotation axis. Actual rates of alignment are probably determined by creeping or cracking of the solid mantle.