Citation

Laurson L, Illa X, Santucci S, Tore Tallakstad K, Måløy KJ, Alava MJ. Nat. Commun. 2013; 4: 2927.

Affiliation

COMP Centre of Excellence, Department of Applied Physics, P.O. Box 11100, FI-00076 Aalto, Espoo, Finland.

Copyright

(Copyright © 2013, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1038/ncomms3927

PMID

24352571

Abstract

A multitude of systems ranging from the Barkhausen effect in ferromagnetic materials to plastic deformation and earthquakes respond to slow external driving by exhibiting intermittent, scale-free avalanche dynamics or crackling noise. The avalanches are power-law distributed in size, and have a typical average shape: these are the two most important signatures of avalanching systems. Here we show how the average avalanche shape evolves with the universality class of the avalanche dynamics by employing a combination of scaling theory, extensive numerical simulations and data from crack propagation experiments. It follows a simple scaling form parameterized by two numbers, the scaling exponent relating the average avalanche size to its duration and a parameter characterizing the temporal asymmetry of the avalanches. The latter reflects a broken time-reversal symmetry in the avalanche dynamics, emerging from the local nature of the interaction kernel mediating the avalanche dynamics.

Language: en