Notice:

Evolution of anisotropic turbulence in the fast and slow solar wind: Theory and Solar Orbiter measurements
Author  Adhikari, L.; Zank, G.~P.; Zhao, L.; Telloni, D.; Horbury, T.~S.; Brien, H.; Evans, V.; Angelini, V.; Owen, C.~J.; Louarn, P.; Fedorov, A.; 
Keywords  Parker Data Used; Solar wind; turbulence 
Abstract  \ Aims: Solar Orbiter (SolO) was launched on February 9, 2020, allowing us to study the nature of turbulence in the inner heliopshere. We investigate the evolution of anisotropic turbulence in the fast and slow solar wind in the inner heliosphere using the nearly incompressible magnetohydrodynamic (NI MHD) turbulence model and SolO measurements. \ Methods: We calculated the two dimensional (2D) and the slab variances of the energy in forward and backward propagating modes, the fluctuating magnetic energy, the fluctuating kinetic energy, the normalized residual energy, and the normalized crosshelicity as a function of the angle between the mean solar wind speed and the mean magnetic field (\ensuremath\theta$_UB$), and as a function of the heliocentric distance using SolO measurements. We compared the observed results and the theoretical results of the NI MHD turbulence model as a function of the heliocentric distance. \ Results: The results show that the ratio of 2D energy and slab energy of forward and backward propagating modes, magnetic field fluctuations, and kinetic energy fluctuations increases as the angle between the mean solar wind flow and the mean magnetic field increases from \ensuremath\theta$_UB$ = 0\textdegree to approximately \ensuremath\theta$_UB$ = 90\textdegree and then decreases as \ensuremath\theta$_UB$ \textrightarrow 180\textdegree. We find that solar wind turbulence is a superposition of the dominant 2D component and a minority slab component as a function of the heliocentric distance. We find excellent agreement between the theoretical results and observed results as a function of the heliocentric distance. 
Year of Publication  2021 
Journal  \aap 
Volume  656 
Number of Pages  A6 
Section  
Date Published  dec 
ISBN  
URL  
DOI  10.1051/00046361/202140672 