2016MNRAS.461L..77H

Pulsar glitches, sudden jumps in frequency observed in many radio pulsars, may be the macroscopic manifestation of superfluid vortex avalanches on the microscopic scale. Small-scale quantum mechanical simulations of vortex motion in a decelerating container have shown that such events are possible and predict power-law distributions for the size of the events, and exponential distributions for the waiting time. Despite a paucity of data, this prediction is consistent with the size and waiting time distributions of most glitching pulsars. Nevertheless, a few object appear to glitch quasi-periodically, and exhibit many large glitches, while a recent study of the Crab pulsar has suggested deviations from a power-law distribution for smaller glitches. In this Letter, we incorporate the results of quantum mechanical simulations in a macroscopic superfluid hydrodynamics simulation. We show that the effect of vortex coupling to the neutron and proton fluids in the star naturally leads to deviations from power-law distributions for sizes, and from exponential distributions for waiting times, and we predict a cutoff in the size distribution for small glitches.