The Secular Variation of Pulsar Magnetic Dipole Moments
Abstract
The time dependences of the inertia tensor and of a dissipative torque caused by the nonleptonic weak interaction have been investigated for a certain class of pulsars with no solid core. Early in the life of the pulsar, the angular velocity vector is predicted to move with respect to fixed body axes in such a way that it becomes perpendicular to the magnetic dipole moment. During this motion, the solid outer shell suffers plastic deformation so that the dipole moment becomes approximately collinear with a principal axis. After 10^{4} or 10^{5} yr, the dissipative torque is negligibly small compared with the electromagnetic torque, the Euler equations are those for a simple rigid body, and alignment of spin and dipole moment occurs. If the dipole moment discussed by Lyneet al. (1975) is interpreted as being equal to the component perpendicular to the spin, its secular decay is a natural property of this model and is not a consequence of field decay through electrical resistivity.
 Publication:

Astrophysics and Space Science
 Pub Date:
 December 1976
 DOI:
 10.1007/BF00642671
 Bibcode:
 1976Ap&SS..45..369J
 Keywords:

 Dipole Moments;
 Magnetic Dipoles;
 Pulsars;
 Secular Variations;
 Stellar Magnetic Fields;
 Electrical Resistivity;
 Magnetic Variations;
 Plastic Deformation;
 Spin Dynamics;
 Stellar Evolution;
 Stellar Rotation;
 Torque;
 Astrophysics