Based on Helios measurements, seven quantities of normalized PDF (Probability Distribution Function) associated with magnetic field and its disturbances are utilized to characterize the intermittency in the fast solar wind using Castaing distributions and the idea of "Flatness". The magnetic field fluctuations are found to be more intermittent at farther distances from the sun. The "Flatness" decreases with increasing time scales, with the corresponding PDF eventually approaching Gaussian distributions. Such a transition occurs at a relatively small time scale for the perpendicular component of perturbed field. The increase in "Flatness" with decreasing time scale is more apparent farther from the sun. By examining how the relative energy density of magnetic disturbances at various time scales changes with the mean field, our study supports the idea that the perturbed fields in the fast solar wind in the frequency range considered are consistent with cross-scale redistribution of wave energy favoring larger scales.
|Number of pages
|Journal of Atmospheric and Solar-Terrestrial Physics
|Published - 2010 Jan 1
All Science Journal Classification (ASJC) codes
- Atmospheric Science
- Space and Planetary Science