A possible truncatedLévyflight statistics recovered from interplanetary solarwind velocity and magneticfield fluctuations
Abstract
Interplanetary solarwind fluctuations have been studied in the inner heliosphere and within the MHD range of scales. We found that fluctuations are such that velocity and magneticfield vectors, which initially keep their orientation around a given direction in space during a certain time interval, abruptly change direction to fluctuate around a new orientation. This behavior is then repeated several times per hour. This kind of phenomenon resembles a Lévyflight behavior and stimulated us to compare these observations with a Lévy statistics, particularly sensitive to longrange correlations. In particular, we considered the distribution function of velocity and magneticfield vector differences within fast and slow wind. This analysis showed that our observations can be reasonably fitted by a truncatedLévyflight (TLF) distribution. Moreover, we found a clear radial dependence for the PDFs of these fluctuations to evolve from Gaussianlike to possible TLF only within fast wind. We provide an explanation for what we observe in terms of a competing action between quasistochastic, propagating fluctuations and convected structures, both contributing to solarwind turbulent fluctuations.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 April 2004
 DOI:
 10.1209/epl/i2003101547
 Bibcode:
 2004EL.....66..146B