Interplay between turbulence and waves: large-scale helical transfer, and small-scale dissipation and mixing in fluid and Hall-MHD turbulence

Pouquet, Annick, Rosenberg, Duane and Stawarz, Julia (2020) Interplay between turbulence and waves: large-scale helical transfer, and small-scale dissipation and mixing in fluid and Hall-MHD turbulence. Rendiconti Lincei. Scienze Fisiche e Naturali, 31 (4). pp. 949-961. ISSN 2037-4631

[img]
Preview
Text
LYNC-D-20-00116_R1-1_accepted.pdf - Accepted Version

Download (4MB) | Preview
Official URL: https://doi.org/10.1007/s12210-020-00951-5

Abstract

Novel features of turbulent flows have been analyzed recently, for example: (1) the possibility of an ideal invariant, such as the energy, to be transferred both to the small scales and to the large scales, in each case with a constant flux; (2) the existence of non-Gaussian wings in Probability Distribution Functions of kinetic, magnetic, and temperature fluctuations, together with their gradients, thus displaying large-scale as well as small-scale intermittency; and (3) the linear dependence on the control parameter of the effective dissipation in turbulence when non-linear eddies and waves interact. We shall briefly review these results with examples stemming from Solar Wind data, the atmosphere and the ocean with either magnetic fields, stratification, and/or rotation. In a second part, we shall examine numerically the inverse cascades of magnetic and of generalized helicity for Hall-MHD in the presence of forcing. These helical invariants in the ideal non-dissipative case involve various cross-correlations between the velocity and vorticity, the magnetic field, and the magnetic potential. For an ion inertial length larger than the forcing scale, the effect of the waves is significant. It leads to an exponential attenuation of the inverse cascade to large scales, since, through the velocity and vorticity, small scales play an increasing dynamical role for a strong Hall current.

Item Type: Article
Additional Information: Funding Information: The work of Julia E. Stawarz was supported in part by the project UKR/STFC Grant ST/S000364/1.
Uncontrolled Keywords: Hall-MHD, Helicity, Inverse cascades, Turbulence, Waves
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 19 Jan 2023 14:48
Last Modified: 19 Jan 2023 15:00
URI: https://nrl.northumbria.ac.uk/id/eprint/51209

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year

View more statistics