Characterizing current structures in 3D hybrid-kinetic simulations of plasma turbulence

TL;DR

This paper uses 3D hybrid-kinetic simulations to analyze the shape and magnetic configurations of current structures in plasma turbulence, validating local measurement methods and comparing simulation results with MMS satellite data.

Contribution

It introduces methods to estimate 3D structure shapes from local measurements and compares simulation data with satellite observations to validate the models.

Findings

Local methods effectively estimate 3D structure shapes.

Different turbulent regimes produce distinct magnetic configurations.

Simulations reproduce structures observed in MMS satellite data.

Abstract

In space and astrophysical plasmas turbulence leads to the development of coherent structures characterized by a strong current density and important magnetic shears. Using hybrid-kinetic simulations of turbulence (3D with different energy injection scales) we investigate the development of these coherent structures and characterize their shape. First, we present different methods to estimate the overall shape of the 3D structure using local measurements, foreseeing application on satellite data. Then we study the local magnetic configuration inside and outside current peak regions, comparing the statistics in the two cases. Last, we compare the statistical properties of the local configuration obtained in simulations with the ones obtained analyzing an MMS dataset having similar plasma parameters. Thanks to our analysis, 1) we validate the possibility to study the overall shape of 3D structures using local methods, 2) we provide an overview of local magnetic configuration emerging in different turbulent regimes, 3) we show that our 3D-3V simulations can reproduce the structures that emerge in MMS data for the periods studied by Phan et al. (2018), Stawarz et al. (2019).