The signature of evolving turbulence in quiet solar wind as seen by ULYSSES

Abstract

Solar wind fluctuations, such as magnetic field or velocity, show power law power spectra suggestive both of an inertial range of intermittent turbulence (with $\sim -5/3$ exponent) and at lower frequencies, of fluctuations of coronal origin (with $\sim -1$ exponent). The ULYSSES spacecraft spent many months in the quiet fast solar wind above the Sun's polar coronal holes in a highly ordered magnetic field. We use statistical analysis methods such as the generalized structure function (GSF) and extended self-similarity (ESS) to quantify the scaling of the moments of the probability density function of fluctuations in the magnetic field. The GSFs give power law scaling in the ``$f^{-1}$'' range of the form $<|y(t+\tau )-y(t){|}^m>\sim {\tau }^{\zeta (m)}$, but ESS is required to reveal scaling in the inertial range, which is of the form $<|y(t+\tau )-y(t){|}^m>\sim [g(\tau ){]}^{\zeta (m)}$. We find that $g(\tau )$ is independent of spacecraft position and $g(\tau )\sim {\tau }^{-lo{g}_{10}(\tilde{\lambda }\tau )}$. The ``$f^{-1}$'' scaling fluctuates with radial spacecraft position. This confirms that, whereas the ``$f^{-1}$'' fluctuations are directly influenced by the corona, the inertial range fluctuations are consistent with locally evolving turbulence, but with an ``envelope'' $g(\tau )$, which captures the formation of the quiet fast solar wind.

arXiv comment16 pages, 12 figures, to be presented at Fall AGU 2007 in San Fransisco

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• Observation of inertial energy cascade in interplanetary space plasma
• Radial evolution of solar wind intermittency in the inner heliosphere
• Application of extended self similarity in turbulence
• A method for extracting the scaling exponents of a self-affine, non-Gaussian process from a finite length timeseries
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Cited by in corpus (12)

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• Self-consistent Castaing distribution of solar wind turbulent fluctuations
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• Turbulent characteristics in the intensity fluctuations of a solar quiescent prominence observed by the \textit{Hinode} Solar Optical Telescope
• Multifractal Analysis of Heliospheric Magnetic Field Fluctuations observed by Ulysses
• Reconnection-Driven Magnetohydrodynamic Turbulence in a Simulated Coronal-Hole Jet
• Quantifying the Anisotropy and Solar Cycle Dependence of "$1/f$" Solar Wind Fluctuations Observed by Ace
• The scale-free texture of the fast solar wind
• Generalized similarity in finite range solar wind magnetohydrodynamic turbulence
• Pseudo-nonstationarity in the scaling exponents of finite interval time series
• Deciphering solar turbulence from sunspots records