Observation of Chaotic fluctuations in Turbulent Plasma

TL;DR

This paper provides the first in-situ evidence that turbulent solar wind plasma downstream of Earth's bow shock exhibits chaotic fluctuations, challenging the conventional view of plasma turbulence as purely stochastic.

Contribution

It demonstrates that magnetosheath plasma turbulence can display chaotic behavior, using permutation entropy-complexity analysis, which is a novel approach in this context.

Findings

Magnetosheath turbulence shows characteristics of chaos rather than stochasticity.

Permutation entropy-complexity analysis effectively distinguishes chaotic from stochastic plasma fluctuations.

Challenging the traditional view, the study suggests caution in using magnetosheath as a turbulence laboratory.

Abstract

Turbulence is a prevalent phenomenon in space and astrophysical plasmas, often characterized by stochastic fluctuations. While laboratory experiments and numerical simulations have revealed chaotic behavior, in-situ observations of turbulent plasmas in natural environments have predominantly shown highly stochastic signatures. Here, we present unprecedented in-situ evidence of chaotic fluctuations in the turbulent solar wind plasma downstream of the Earth's bow shock. By analyzing the relative location of magnetic-field fluctuations on the permutation entropy-complexity plane (C-H plane), we demonstrate that turbulence in the magnetosheath plasma exhibits characteristics of chaotic fluctuations rather than stochastic behavior, diverging from the expected traits of well-developed turbulence. This finding challenges established notions of plasma turbulence and reveals the need for caution when using the magnetosheath as a laboratory for studying plasma turbulence.