Colloquium:: Experiments in vortex avalanches

Avalanche dynamics are found in many phenomena, from earthquakes to the evolution of species. They can also be found in vortex matter when a type-II superconductor is externally driven, for example, by an increasing magnetic field. Vortex avalanches associated with thermal instabilities can be an undesirable effect for applications, but "dynamically driven" avalanches emerging from the competition between intervortex interactions and quenched disorder may provide an interesting test scenario for nonequilibrium dynamics theory. In contrast to the equilibrium phases of vortex matter in type-II superconductors, the corresponding dynamical phases-in which avalanches can play a role-are only beginning to be studied. This article reviews relevant experiments performed in the last decade or so, emphasizing the ability of different experimental techniques to establish the nature and statistical properties of avalanche behavior.