Theory 07/Physics, Cosmos & Matter /Neutron stars
Glitches Are Avalanches
A glitch is modelled as a region letting go. It may be one defect triggering others.
Pulsar glitches are avalanche events in a pinned vortex lattice rather than sudden unpinning of a whole region, so their size distribution should follow a power law and their waiting times a characteristic scaling.
01The evidence
Glitch sizes span orders of magnitude and occur irregularly, which is the signature of avalanche dynamics rather than of a threshold release.
02The tension
Models invoke a critical strain at which a region unpins, which predicts a characteristic size. The observed distribution is broad.
03The mechanism
Vortices pin on lattice defects. A small perturbation can unpin one, which shifts stress to its neighbours and triggers a cascade whose size is set by how close the lattice is to the critical state.
That makes the crust a self-organised critical system, and predicts a power-law size distribution with an exponent that should be measurable.
04What this is not
Those models predict a characteristic size. This predicts a power law, which matches the data.
05Predictions
- P1Glitch sizes should follow a power law.
- P2Waiting times should scale.
- P3The exponent should be universal across pulsars.
06Refutation
A characteristic glitch size would refute the avalanche picture.
07What it changes
It would connect glitches to crustal criticality.