Turbulent Density Spectrum in Solar Wind Plasma

Abstract

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence, over extended length-scales remains an unresolved paradox of modern turbulence theories, raising the question of how a compressible magnetofluid exhibits a turbulent spectrum that is characteristic of an incompressible hydrodynamic fluid. To address these questions, we have undertaken three-dimensional time dependent numerical simulations of a compressible magnetohydrodynamic fluid describing super-Alfvénic, supersonic and strongly magnetized plasma fluid. It is shown that a Kolmogorov-like density spectrum can develop by plasma motions that are dominated by Alfvénic cascades whereas compressive modes are dissipated.

Paper is to appear in Monthly Notices of the Royal Astronomical Society Main Journal

References in corpus (5)

• The Statistics of Supersonic Isothermal Turbulence
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• Probing Current Sheet Instabilities from Flare Ribbon Dynamics
• Turbulent density fluctuations and proton heating rate in the solar wind from 9-20~R_{\odot}
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• Evidence of Nonlinear Signatures in Solar Wind Proton Density at the L1 Lagrange point