Event Details

MARS (Mathematics for AI in Real-world Systems) seminar series. Speaker: Andrew Baggaley (Lancaster). Title: Vortex avalanches and collective motion in neutron stars.

Abstract: We study the dynamics of quantum vortices in a spinning-down cylindrical container using a nonlinear Schrödinger model.We find convincing spatial-temporal evidence of avalanching behaviour resulting from vortex depinning and collective motion. During a typical avalanche, O(10) vortices exit the container in a short period, producing a glitch in the superfluid angular momentum and a localised void in the vorticity. After the glitch, vortices continue to depin and circulate around the vorticity void in a similar manner to that seen in previous point-vortex approaches. We present evidence of collective vortex motion throughout this avalanche process. We also show that the effective Magnus force can be used to predict when and where avalanches will occur. Finally, we comment on the challenge of extrapolating these results to conditions in real neutron stars, which contain many orders of magnitude more vortices.