The Complex Structure of Magnetic Field Discontinuities in the Turbulent Solar Wind

TL;DR

This study reveals that magnetic discontinuities in the turbulent solar wind exist across multiple scales, resembling plasma equilibria, and are interconnected through a self-similar cascade involving magnetic reconnection and secondary islands.

Contribution

It demonstrates the multiscale, interconnected structure of magnetic discontinuities in the solar wind and links observational data with reconnection-driven turbulence models.

Findings

Magnetic discontinuities span from proton to electron scales.

Structures resemble Harris equilibrium profiles.

Reconnection processes produce complex, self-similar networks of secondary islands.

Abstract

Using high resolution Cluster satellite observations, we show that the turbulent solar wind is populated by magnetic discontinuities at different scales, going from proton down to electron scales. The structure of these layers resembles the Harris equilibrium profile in plasmas. Using a multi-dimensional intermittency technique, we show that these structures are connected through the scales. Supported by numerical simulations of magnetic reconnection, we show that observations are consistent with a scenario where many current layers develop in turbulence, and where the outflow of these reconnection events are characterized by complex sub-proton networks of secondary islands, in a self-similar way. The present work establishes that the picture of "reconnection in turbulence" and "turbulent reconnection", separately invoked as ubiquitous, coexist in space plasmas.