Occurrence Rates and Heating Effects of Tangential and Rotational Discontinuities as Obtained from Three-dimensional Simulation of Magnetohydrodynamic Turbulence

Abstract

In solar wind, magnetohydrodynamic (MHD) discontinuities are ubiquitous and often found to be at the origin of turbulence intermittency. They may also play a key role in the turbulence dissipation and heating of the solar wind. The tangential (TD) and rotational (RD) discontinuities are the two most important types of discontinuities. Recently, the connection between turbulence intermittency and proton thermodynamics has been being investigated observationally. Here we present numerical results from three-dimensional MHD simulation with pressure anisotropy and define new methods to identify and to distinguish TDs and RDs. Three statistical results obtained about the relative occurrence rates and heating effects are highlighted: (1) RDs tend to take up the majority of the discontinuities along with time; (2) the thermal states embedding TDs tend to be associated with extreme plasma parameters or instabilities, while RDs do not; (3) TDs have a higher average T as well as perpendicular temperature $T_{\perp }$. The simulation shows that TDs and RDs evolve and contribute to solar wind heating differently. These results will inspire our understanding of the mechanisms that generate discontinuities and cause plasma heating.

arXiv comment5 Figures, Submitted to Astrophys. J. Lett., in the process of refereeing

References in corpus (5)

• Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind
• Radiative MHD simulation of sunspot structure
• Kinetic dissipation and anisotropic heating in a turbulent collisionless plasma
• Kinetic Signatures and Intermittent Turbulence in the Solar Wind Plasma
• Proton Kinetic Effects in Vlasov and Solar Wind Turbulence

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• On the Existence of Fast Modes in Compressible Magnetohydrodynamic Turbulence
• Magnetic Field Rotations in the Solar Wind at Kinetic Scales
• Turbulence-generated proton-scale structures in the terrestrial magnetosheath
• Contribution of Magnetic Reconnection Events to Energy Dissipation in Magnetosheath Turbulence
• Multi-scale Pressure-balanced Structures in Three-dimensional Magnetohydrodynamic Turbulence