Small Scale Energy Cascade of the Solar Wind Turbulence

Abstract

Magnetic fluctuations in the solar wind are distributed according to Kolmogorov's power law $f^{-5/3}$ below the ion cyclotron frequency $f_{ci}$. Above this frequency, the observed steeper power law is usually interpreted in two different ways: a dissipative range of the solar wind turbulence or another turbulent cascade, the nature of which is still an open question. Using the Cluster magnetic data we show that after the spectral break the intermittency increases toward higher frequencies, indicating the presence of non-linear interactions inherent to a new inertial range and not to the dissipative range. At the same time the level of compressible fluctuations raises. We show that the energy transfer rate and intermittency are sensitive to the level of compressibility of the magnetic fluctuations within the small scale inertial range. We conjecture that the time needed to establish this inertial range is shorter than the eddy-turnover time, and is related to dispersive effects. A simple phenomenological model, based on the compressible Hall MHD, predicts the magnetic spectrum $\sim k^{-7/3+2\alpha }$, which depends on the degree of plasma compression $\alpha$.

accepted for publication in The Astrophysical Journal the 1st of October 2007

References in corpus (3)

• Wave turbulence in incompressible Hall MHD
• Multi-scale Hall-MHD turbulence in the solar wind
• On the Rapid Increase of Intermittency in the Near-Dissipation Range of Fully Developed Turbulence

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• Simulations of Electron Magnetohydrodynamic Turbulence
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• Spectral Slope Variation at Proton Scales from Fast to Slow Solar Wind
• Kinetic cascade in solar-wind turbulence: 3D3V hybrid-kinetic simulations with electron inertia
• Intermittency of Solar Wind Density Fluctuations From Ion to Electron Scales
• Plasma beta dependence of the ion-scale spectral break of solar wind turbulence: high-resolution 2D hybrid simulations
• Kinetic cascade beyond magnetohydrodynamics of solar wind turbulence in two-dimensional hybrid simulations
• Coherent structures at ion scales in fast solar wind: {\it Cluster} observations
• Solar wind turbulence from MHD to sub-ion scales: high-resolution hybrid simulations
• The Violation of the Taylor Hypothesis in Measurements of Solar Wind Turbulence
• Magnetic turbulence spectra and intermittency in the heliosheath and in the local interstellar medium
• Nonlinear and Linear Timescales near Kinetic Scales in Solar Wind Turbulence
• Whistler Wave Cascade in Solar Wind Plasma
• Dynamic anisotropy in MHD turbulence induced by mean magnetic field
• Intermittency in the Expanding Solar Wind: Observations from Parker Solar Probe (0.16au), Helios 1 (0.3-1au), and Voyager 1 (1-10au)
• Revisiting a classic: the Parker-Moffatt problem
• Extended MHD turbulence and its applications to the solar wind
• Variability Of The Magnetic Field Power Spectrum In The Solar Wind At Electron Scales
• Multifractal Analysis of Heliospheric Magnetic Field Fluctuations observed by Ulysses
• Anisotropies of the magnetic field fluctuations at kinetic scales in the solar wind : Cluster observations
• Linking Fluid and Kinetic Scales in Solar Wind Turbulence
• A Model for Dissipation of Solar Wind Magnetic Turbulence by Kinetic Alfvén Waves at Electron Scales: Comparison with Observations
• Dissipation scale lengths of density turbulence in the inner solar wind
• Effects of the Background Turbulence on the Relaxation of Ion Temperature Anisotropy in Space Plasmas
• Simulations of Energetic Particles Interacting with Nonlinear Anisotropic Dynamical Turbulence
• Current sheets, plasmoids and flux ropes in the heliosphere. Part II: Theoretical aspects