Are Avalanches in Sandpiles a Chaotic Phenomenon?

TL;DR

This paper demonstrates that deterministic nonlinear models, especially chaotic ones, better explain sandpile behavior and the breakdown of Self-Organized Criticality observed in experiments, highlighting chaos's fundamental role.

Contribution

It introduces a deterministic nonlinear model that reproduces experimental sandpile phenomena and clarifies the role of chaos in their dynamics.

Findings

Reproduces breakdown of Self-Organized Criticality in experiments

Shows chaos is fundamental to sandpile dynamics

Models recover SOC by parameter variation

Abstract

We show that deterministic systems with strong nonlinearities seem to be more appropriate to model sandpiles than stochastic systems or deterministic systems in which discontinuities are the only nonlinearity. In particular, we are able to reproduce the breakdown of Self-Organized Criticality found in two well known experiments, that is, a centrally fueled pile [Held et al. Phys. Rev. Lett. 65 (1990) 1120] and sand in a rotating tray [Bretz et al. Phys. Rev. Lett. 69 (1992) 2431]. By varying the parameters of the model we recover Self-Organized Criticality, in agreement with other experiments and other models. We show that chaos plays a fundamental role in the dynamics of the system.