Observational Constraints on the Internal Structure and Dynamics of the Vela Pulsar

Abstract

We show that the short spin-up timeobserved for the Vela pulsar during the 1988 "Christmas" glitch impliesthat the coupling time of the pulsar core to its crust is less than~10 s. Ekman pumping cannot explain the fast core-crust couplingand a more effective coupling is necessary. The internal magneticfield of the Vela pulsar can provide the necessary coupling if thefield threads the core with a magnitude that exceeds 1013 G for anormal interior and 1011 G for a superconducting interior. Theselower bounds favor the hypothesis that the interior of neutron starscontains superfluid neutrons and protons and challenge the notionthat pulsar magnetic fields decay over million year timescales orthat magnetic flux is expelled from the core as the star slows.