Appearance and nonappearance of self-organized criticality in sandpiles

Self-organized criticality (SOC) often features in sandpile-type modeling of complex systems such as magnetic fusion plasmas, but its observed role in real sandpiles is equivocal. Here, a probabilistic model displaying some of the observed phenomenology of real sandpiles is proposed. It generates avalanches involving particle loss that, like most experiments, do not exhibit SOC, but its internal energy avalanches resemble recent experiments by showing SOC. This suggests that the absence of SOC in the flow of matter from such systems can be consistent with internal dynamics governed by SOC.