Multi-Spacecraft Measurement of Turbulence within a Magnetic Reconnection Jet

TL;DR

This study uses multipoint spacecraft measurements to analyze turbulence within a magnetic reconnection jet, revealing intermittent energy conversion and multifractal magnetic fluctuations, with implications for space plasma turbulence.

Contribution

It provides the first detailed multipoint analysis linking electromagnetic work, turbulence, and energy dissipation in a reconnection jet.

Findings

Electromagnetic work distribution is non-Gaussian and concentrated in high-current regions.

Magnetic fluctuations exhibit multifractal scaling and non-Gaussian invariance.

Turbulent dissipation occurs via intermittent, coherent structures.

Abstract

The relationship between magnetic reconnection and plasma turbulence is investigated using multipoint in-situ measurements from the Cluster spacecraft within a high-speed reconnection jet in the terrestrial magnetotail. We show explicitly that work done by electromagnetic fields on the particles, $\mathbf{J}\cdot\mathbf{E}$, has a non-Gaussian distribution and is concentrated in regions of high electric current density. Hence, magnetic energy is converted to kinetic energy in an intermittent manner. Furthermore, we find the higher-order statistics of magnetic field fluctuations generated by reconnection are characterized by multifractal scaling on magnetofluid scales and non-Gaussian global scale invariance on kinetic scales. These observations suggest $\mathbf{J}\cdot\mathbf{E}$ within the reconnection jet has an analogue in fluid-like turbulence theory in that it proceeds via coherent structures generated by an intermittent cascade. This supports the hypothesis that turbulent dissipation is highly nonuniform, and thus these results could have far reaching implications for space and astrophysical plasmas.