Defect turbulence and generalized statistical mechanics

TL;DR

This paper provides experimental evidence that defect motion in thermal convection patterns can be modeled using Tsallis statistics, revealing nonextensive behavior with an entropic index around 1.5, and aligns well with nonextensive model predictions.

Contribution

It demonstrates the applicability of Tsallis nonextensive statistics to describe defect dynamics in thermal convection, a novel experimental validation of this theoretical framework.

Findings

Defects exhibit anomalous diffusion and non-Gaussian velocity distributions.

Velocity correlations decay as a power law, consistent with nonextensive predictions.

The entropic index q is approximately 1.5 across various conditions.

Abstract

We present experimental evidence that the motion of point defects in thermal convection patterns in an inclined fluid layer is well-described by Tsallis statistics with an entropic index $q \approx 1.5$. The dynamical properties of the defects (anomalous diffusion, shape of velocity distributions, power law decay of correlations) are in good agreement with typical predictions of nonextensive models, over a range of driving parameters.