Solar Wind Turbulence: the Effects of Spherical Expansion on II and III Order Structure Functions
Solar Wind Turbulence: the Effects of Spherical Expansion on II and III Order Structure Functions
French Title: La Turbulence dans le Vent Solair: les Effets de l'Expansion Sphérique sur les Fonctions de Structure d'ordre II et III
Previously Published Material: Some of the result will be also presented at EGU 2015 meetingPart of the results are contained in a paper currently under review
Abstract ID#: 34936
English Abstract:
The Expanding Box Model (EBM) is a framework for numerical simulations of turbulence that is able to capture the effect of spherical expansion while retaining the resolution for turbulence dynamics. We have recently shown that it can reproduce two important feature of solar wind turbulence, namely the component anisotropy and the emergence of jets at large scales. We present now an analysis of the simulated solar wind turbulence in terms of II-order and III-order structure function (SF).
We find that EBM simulations are able to reproduce the observed II-order SF anisotropy with respect to the local mean field (eddy shape) and further show that the overall anisotropy depends on the direction of increments on which SF are calculated. We finally present preliminary results on III-order SF in the EBM and compare them to homogenous turbulence simulations (MHD and Hybrid-PIC) in order to highlight the effects of expansion on the III-order SF anisotropy and the resulting cascade rate.
We find that EBM simulations are able to reproduce the observed II-order SF anisotropy with respect to the local mean field (eddy shape) and further show that the overall anisotropy depends on the direction of increments on which SF are calculated. We finally present preliminary results on III-order SF in the EBM and compare them to homogenous turbulence simulations (MHD and Hybrid-PIC) in order to highlight the effects of expansion on the III-order SF anisotropy and the resulting cascade rate.