Evolution of Intermittency in the Slow and Fast Solar Wind Beyond the Ecliptic Plane

TL;DR

This study analyzes how intermittency in solar wind magnetic turbulence evolves with distance and latitude beyond the ecliptic plane, revealing slow changes and hemispheric symmetry, with implications for solar origin of turbulence.

Contribution

It provides the first detailed analysis of intermittency evolution in the slow and fast solar wind beyond the ecliptic plane using multifractal modeling of Ulysses data.

Findings

Intermittency decreases slowly with distance and latitude.

Multifractality is lower than in the ecliptic.

Hemispheric symmetry in turbulent properties.

Abstract

We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997-1998 and 2007-2008) and one solar maximum (1999-2001). In particular, by modeling a multifractal spectrum, we revealed the intermittent character of turbulence in the small-scale fluctuations of the magnetic field embedded in the slow and fast solar wind. Generally, at small distances from the Sun, in both the slow and fast solar wind, we observe the high degree of multifractality (intermittency) that decreases somewhat slowly with distance and slowly with latitude. The obtained results seem to suggest that generally intermittency in the solar wind has a solar origin. However, the fast and slow streams, shocks, and other nonlinear interactions can only be considered as the drivers of the intermittent turbulence. It seems that analysis shows that turbulence beyond the ecliptic plane evolves too slowly to maintain the intermittency with the distance and latitude. Moreover, we confirm that the multifractality and intermittency are at a lower level than in the ecliptic, as well as the existence of symmetry with respect to the ecliptic plane, suggesting that there are similar turbulent properties observed in the two hemispheres.