Ion-scale transition of plasma turbulence: Pressure-strain effect

TL;DR

This study uses hybrid simulations and an extended Karman-Howarth-Monin equation to analyze the transition from MHD to ion scales in plasma turbulence, highlighting the roles of Hall physics and pressure-strain effects.

Contribution

It introduces a novel application of the KHM equation to compressible Hall MHD, revealing the pressure-strain effect's role in plasma turbulence transition.

Findings

Transition involves Hall physics onset and pressure-strain dissipation.

Pressure-strain energy exchange contributes to turbulence dissipation.

Results are relevant for understanding solar wind turbulence.

Abstract

We investigate properties of solar wind-like plasma turbulence using direct numerical simulations. We analyze the transition from large, magnetohydrodynamic (MHD) scales to the ion characteristic ones using two-dimensional hybrid (fluid electrons, kinetic ions) simulations. To capture and quantify turbulence properties, we apply the Karman-Howarth-Monin (KHM) equation for compressible Hall MHD (extended by considering the plasma pressure as a tensor quantity) to the numerical results. The KHM analysis indicates that the transition from MHD to ion scales (the so called ion break in the power spectrum) results from a combination of an onset of Hall physics and of an effective dissipation owing to the pressure-strain energy-exchange channel and resistivity. We discuss the simulation results in the context of the solar wind.