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Title: SOLAR WIND TURBULENCE FROM MHD TO SUB-ION SCALES: HIGH-RESOLUTION HYBRID SIMULATIONS

We present results from a high-resolution and large-scale hybrid (fluid electrons and particle-in-cell protons) two-dimensional numerical simulation of decaying turbulence. Two distinct spectral regions (separated by a smooth break at proton scales) develop with clear power-law scaling, each one occupying about a decade in wavenumbers. The simulation results simultaneously exhibit several properties of the observed solar wind fluctuations: spectral indices of the magnetic, kinetic, and residual energy spectra in the magnetohydrodynamic (MHD) inertial range along with a flattening of the electric field spectrum, an increase in magnetic compressibility, and a strong coupling of the cascade with the density and the parallel component of the magnetic fluctuations at sub-proton scales. Our findings support the interpretation that in the solar wind, large-scale MHD fluctuations naturally evolve beyond proton scales into a turbulent regime that is governed by the generalized Ohm’s law.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Dipartimento di Fisica e Astronomia, Università di Firenze, Largo E. Fermi 2, I-50125 Firenze (Italy)
  2. Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom)
  3. Astronomical Institute, AS CR, Bocni II/1401, CZ-14100 Prague (Czech Republic)
Publication Date:
OSTI Identifier:
22518976
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 804; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPRESSIBILITY; COMPUTERIZED SIMULATION; COSMIC ELECTRONS; COSMIC PROTONS; DENSITY; ELECTRIC FIELDS; ENERGY SPECTRA; FLUCTUATIONS; MAGNETOHYDRODYNAMICS; PLASMA; RESOLUTION; SOLAR WIND; SUN; TURBULENCE