Complexity of magnetic-field turbulence at reconnection exhausts in the solar wind at 1 AU

TL;DR

This study investigates magnetic-field turbulence at solar wind reconnection exhausts, revealing that coherent structures influence turbulence complexity and intermittency, with implications for understanding space plasma dynamics.

Contribution

It applies the Jensen-Shannon complexity-entropy index to analyze turbulence at reconnection exhausts, linking intermittency to entropy and complexity variations across magnetic field components.

Findings

Higher intermittency correlates with lower entropy and higher complexity.

The $B_L$ component shows lower entropy and higher complexity than $B_M$ and $B_N$.

Coherent structures are associated with decreased entropy and increased complexity.

Abstract

Magnetic reconnection is a complex mechanism that converts magnetic energy into particle kinetic energy and plasma thermal energy in space and astrophysical plasmas. In addition, magnetic reconnection and turbulence appear to be intimately related in plasmas. We analyze the magnetic-field turbulence at the exhaust of four reconnection events detected in the solar wind using the Jensen-Shannon complexity-entropy index. The interplanetary magnetic field is decomposed into the LMN coordinates using the hybrid minimum variance technique. The first event is characterized by an extended exhaust period that allows us to obtain the scaling exponents of higher-order structure functions of magnetic-field fluctuations. By computing the complexity-entropy index we demonstrate that a higher degree of intermittency is related to lower entropy and higher complexity in the inertial subrange. We also compute the complexity-entropy index of three other reconnection exhaust events. For all four events, the $B_L$ component of the magnetic field displays a lower degree of entropy and higher degree of complexity than the $B_M$ and $B_N$ components. Our results show that coherent structures can be responsible for decreasing entropy and increasing complexity within reconnection exhausts in magnetic-field turbulence.