Speaker
Description
Many neutron stars exhibit rotational 'glitches' caused by the collective depinning of $>10^7$ superfluid vortices. Gross–Pitaevskii (GP) and point-vortex (PV) simulations have demonstrated glitching behaviour via development of vortex avalanches with $500$-$5000$ vortices. Given that a real neuron star contains more than $>10^{13}$ vortices, simulating glitches in a global-scale model requires averaging over many vortices. We develop a hydrodynamic model describing the evolution of vortex density in terms of pinned and free components. The corresponding system of partial differential equations is solved using the pseudospectral method with Dedalus v3 code. We find that multiple glitches arise as hydrodynamic shear instabilities within a certain parameter regime, and are qualitatively similar to dynamics seen in GP and PV simulations. These results suggest that vortex avalanches persist in a coarse-grained model, representing a step toward bridging microscopic and macroscopic descriptions of neutron star crusts.