Unpinning triggers for superfluid vortex avalanches

L. Warszawski, A. Melatos, N. G. Berloff

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)

Abstract

The pinning and collective unpinning of superfluid vortices in a decelerating container is a key element of the canonical model of neutron star glitches and laboratory spin-down experiments with helium II. Here the dynamics of vortex (un-)pinning is explored using numerical Gross-Pitaevskii calculations, with a view to understanding the triggers for catastrophic unpinning events (vortex avalanches) that lead to rotational glitches. We explicitly identify three triggers: rotational shear between the bulk condensate and the pinned vortices, a vortex proximity effect driven by the repulsive vortex-vortex interaction, and sound waves emitted by moving and repinning vortices. So long as dissipation is low, sound waves emitted by a repinning vortex are found to be sufficiently strong to unpin a nearby vortex. For both ballistic and forced vortex motion, the maximum inter-vortex separation required to unpin scales inversely with pinning strength.

Original languageEnglish
Article number104503
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number10
DOIs
Publication statusPublished - 6 Mar 2012
Externally publishedYes

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