Turbulence and Transport During Guide-Field Reconnection at the Magnetopause

TL;DR

This study uses 3D particle-in-cell simulations to analyze turbulence during guide-field magnetic reconnection at the magnetopause, revealing how turbulence influences plasma transport and differs near the X-line from lower hybrid drift instability.

Contribution

It demonstrates the role of turbulence in controlling density and current profiles and highlights the significance of anomalous viscosity near the X-line, based on simulation and observational comparison.

Findings

Turbulence near separatrices is a variant of LHDI with large electric field fluctuations.

Turbulence influences the scale length of density and current profiles.

Simulations suggest MMS spacecraft were not close enough to observe anomalous viscosity effects.

Abstract

We analyze the development and influence of turbulence in three-dimensional particle-in-cell simulations of guide-field magnetic reconnection at the magnetopause with parameters based on observations of an electron diffusion region by the Magnetospheric Multiscale (MMS) mission. Along the separatrices the turbulence is a variant of the lower hybrid drift instability (LHDI) that produces electric field fluctuations with amplitudes much greater than the reconnection electric field. The turbulence controls the scale length of the density and current profiles while enabling significant transport across the magnetopause despite the electrons remaining frozen-in to the magnetic field. Near the X-line the electrons are not frozen-in and the turbulence, which differs from the LHDI, makes a significant net contribution to the generalized Ohm's law through an anomalous viscosity. The characteristics of the turbulence and associated particle transport are consistent with fluctuation amplitudes in the MMS observations. However, for this event the simulations suggest that the MMS spacecraft were not close enough to the core of the electron diffusion region to identify the region where anomalous viscosity is important.