Statistical Analysis of Field-Aligned Alfvénic Turbulence and Intermittency in Fast Solar Wind

摘要

The statistical properties of fast Alfvénic solar wind turbulence have been analyzed by means of empirical mode decomposition and the associated Hilbert spectral analysis. The stringent criteria employed for the data selection in the Wind spacecraft database, has made possible to sample multiple k ‖ field-aligned intervals of the three magnetic field components. The results suggest that the spectral anisotropy predicted by the critical balance theory is not observed in the selected database, whereas a Kolmogorov-like scaling ( E ( k ‖ ) ～ k ? 5 / 3 ) and a weak or absent level of intermittency are robust characteristics of the Alfvénic slab component of solar wind turbulence.