Intermittency and geometrical statistics of three-dimensional homogeneous magnetohydrodynamic turbulence: A wavelet viewpoint

Journal Article · Thu Sep 15 00:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3628637· OSTI ID:22043488

Yoshimatsu, Katsunori; Kawahara, Yasuhiro ^[1]; Schneider, Kai ^[2]; Okamoto, Naoya ^[3]; Farge, Marie ^[4]

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1. Department of Computational Science and Engineering, Nagoya University, Nagoya 464-8603 (Japan)
2. M2P2-CNRS and CMI, Universite de Provence, 39 rue Frederic Joliot-Curie, 13453 Marseille Cedex 13 (France)
3. Center for Computational Science, Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)
4. LMD-IPSL-CNRS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris Cedex 05 (France)

Scale-dependent and geometrical statistics of three-dimensional incompressible homogeneous magnetohydrodynamic turbulence without mean magnetic field are examined by means of the orthogonal wavelet decomposition. The flow is computed by direct numerical simulation with a Fourier spectral method at resolution 512{sup 3} and a unit magnetic Prandtl number. Scale-dependent second and higher order statistics of the velocity and magnetic fields allow to quantify their intermittency in terms of spatial fluctuations of the energy spectra, the flatness, and the probability distribution functions at different scales. Different scale-dependent relative helicities, e.g., kinetic, cross, and magnetic relative helicities, yield geometrical information on alignment between the different scale-dependent fields. At each scale, the alignment between the velocity and magnetic field is found to be more pronounced than the other alignments considered here, i.e., the scale-dependent alignment between the velocity and vorticity, the scale-dependent alignment between the magnetic field and its vector potential, and the scale-dependent alignment between the magnetic field and the current density. Finally, statistical scale-dependent analyses of both Eulerian and Lagrangian accelerations and the corresponding time-derivatives of the magnetic field are performed. It is found that the Lagrangian acceleration does not exhibit substantially stronger intermittency compared to the Eulerian acceleration, in contrast to hydrodynamic turbulence where the Lagrangian acceleration shows much stronger intermittency than the Eulerian acceleration. The Eulerian time-derivative of the magnetic field is more intermittent than the Lagrangian time-derivative of the magnetic field.

• OSTI ID: 22043488
• Journal Information: Physics of Plasmas, Vol. 18, Issue 9; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
COMPUTERIZED SIMULATION
CURRENT DENSITY
DECOMPOSITION
DISTRIBUTION
DISTRIBUTION FUNCTIONS
ENERGY SPECTRA
FLUCTUATIONS
LAGRANGIAN FUNCTION
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
PRANDTL NUMBER
PROBABILITY
RESOLUTION
STATISTICS
TURBULENCE
VORTICES