Vortex unpinning due to crustquake-initiated neutron excitation and pulsar glitches

Abstract

Pulsars undergoing crustquake release strain energy, which can be absorbed in a small region inside the inner crust of the star and excite the free superfluid neutrons therein. The scattering of these neutrons with the surrounding pinned vortices may unpin a large number of vortices and effectively reduce the pinning force on vortex lines. Such unpinning by neutron scattering can produce glitches for Crab-like pulsars and Vela pulsar of size in the range of ∼10−8–10−7 and ∼10−9–10−8, respectively. Although we discuss here the crustquake-initiated excitation, the proposal is very generic and equally applicable for any other sources, which can excite the free superfluid neutrons, or can be responsible for superfluid – normal phase transition of neutron superfluid in the inner crust of a pulsar.