Self-organized criticality

Summary

Self-organized criticality is the property of some slowly driven dynamical systems to evolve by themselves into a critical state. In that state they show scale invariance, such as avalanches of all sizes with a power-law size distribution. No parameter needs to be tuned to a critical value. Ordinary critical phenomena need a tuned parameter, such as the temperature of a magnet. The idea was proposed by Per Bak, Chao Tang and Kurt Wiesenfeld in 1987, with the abelian sandpile model as the first example.