Poster Presentation

Vortex avalanches and collective motions in neutron star interiors

Author(s): Gary Liu, Andrew W. Baggaley, Carlo F. Barenghi, Toby S. Wood (School of Mathematics, Statistics and Physics, Newcastle University, UK)

Presenter: Gary Liu (Newcastle University)

Glitches in neutron stars result from angular momentum exchange between the superfluid in the star's crust and the rest of the star. Most glitching stars exhibit a power law distribution of glitch sizes and an exponential distribution of glitch waiting times, which can be explained in terms of avalanches of quantised vortices in the crust. In this presentation, we investigate the evolution of up to 600 vortices in a spinning-down container using a Gross-Pitaevskii model. For slow spin-down rates, we observe a sequence of avalanches, each involving ~20 vortices. We show that avalanches are triggered in regions where Magnus forces are largest. Each avalanche creates a region of low vorticity that propagates inward as vortices are redistributed in the crust. We present evidence of collective vortex motion both during and after each glitch. For faster spin-down rates we observe many overlapping mini-avalanches, which could be connected with timing noise.