On the Scaling Properties of Magnetic-field Fluctuations through the Inner Heliosphere

Author
Keywords
Abstract
<p>Although the interplanetary magnetic-field variability has been extensively investigated in situ using data from several space missions, newly launched missions providing high-resolution measures and approaching the Sun offer the possibility to study the multiscale variability in the innermost\&nbsp;solar\&nbsp;system. Here, using\&nbsp;Parker\&nbsp;Solar\&nbsp;Probe\&nbsp;measurements, we investigate the scaling properties of\&nbsp;solar\&nbsp;wind magnetic-field fluctuations at different heliocentric distances. The results show a clear transition at distances close to say 0.4 au. Closer to the Sun fluctuations show af(-3/2)frequency power spectra and regular scaling properties, while for distances larger than 0.4 au fluctuations show a Kolmogorov spectrumf(-5/3)and are characterized by anomalous scalings. The observed statistical properties of turbulence suggest that the\&nbsp;solar\&nbsp;wind magnetic fluctuations, in the late stage far from the Sun, show a multifractal behavior typical of turbulence and described by intermittency, while in the early stage, when leaving the\&nbsp;solar\&nbsp;corona, a breakdown of these properties is observed, thus showing a statistical monofractal global self-similarity. Physically, the breakdown observed close to the Sun should be due either to a turbulence with regular statistics or to the presence of intense stochastic fluctuations able to cancel out the correlations necessary for the presence of anomalous scaling.</p>
Year of Publication
2020
Journal
The Astrophysical Journal
Volume
902
Number
Number of Pages
84
Date Published
10/2020
URL
https://iopscience.iop.org/article/10.3847/1538-4357/abb3d2https://iopscience.iop.org/article/10.3847/1538-4357/abb3d2/pdf
DOI
10.3847/1538-4357/abb3d2