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Multifractal scaling of the kinetic energy flux in solar wind turbulenceThe geometrical and scaling properties of the energy flux of the turbulent kinetic energy in the solar wind have been studied. By present experimental technology in solar wind measurements, we cannot directly measure the real volumetric dissipation rate, epsilon(t), but are constrained to represent it by surrogating the energy flux near the dissipation range at the proton gyro scales. There is evidence for the multifractal nature of the so defined dissipation field epsilon(t), a result derived from the scaling exponents of its statistical q-th order moments. The related generalized dimension D(q) has been determined and reveals that the dissipation field has a multifractal structure. which is not compatible with a scale-invariant cascade. The associated multifractal spectrum f(alpha) has been estimated for the first time for MHD turbulence in the solar wind. Its features resemble those obtained for turbulent fluids and other nonlinear multifractal systems. The generalized dimension D(q) can, for turbulence in high-speed streams, be fitted well by the functional dependence of the p-model with a comparatively large parameter, p = 0.87. indicating a strongly intermittent multifractal energy cascade. The experimental value for D(p)/3, if used in the scaling exponent s(p) of the velocity structure function, gives an exponent that can describe some of the observations. The scaling exponent mu of the auto correlation function of epsilon(t) has also been directly evaluated. It has the value of 0.37. Finally. the mean dissipation rate was determined, which could be used in solar wind heating models.
Document ID
19960021423
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Marsch, E.
(Max-Planck-Inst. fuer Aeronomie Katlenburg-Lindau, Germany)
Rosenbauer, H.
(Max-Planck-Inst. fuer Aeronomie Katlenburg-Lindau, Germany)
Tu, C.-Y.
(Peking Univ. China)
Date Acquired
August 17, 2013
Publication Date
June 30, 1995
Subject Category
Solar Physics
Accession Number
96N24819
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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