L. Sorriso-valvo et al., Intermittency in the solar wind turbulence through probability distribution functions of fluctuations, GEOPHYS R L, 26(13), 1999, pp. 1801-1804
Intermittency in fluid turbulence can be emphasized through the analysis of
Probability Distribution Functions (PDF) for velocity fluctuations, which
display a strong non-gaussian behavior at small scales. Castaing et al. (19
90) have introduced the idea that this behavior can be represented, in the
framework of a multiplicative cascade model, by a convolution of gaussians
whose variances is distributed according to a log-normal distribution. In t
his letter we have tried to test this conjecture on the MHD solar wind turb
ulence by performing a fit of the PDF of the bulk speed and magnetic field
intensity fluctuations calculated in the solar wind, with the model. This f
it allows us to calculate a parameter lambda(2) depending on the scale, whi
ch represents the width of the log-normal distribution of the variances of
the gaussians. The physical implications of the obtained values of the para
meter as well as of its scaling law are finally discussed.