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Prof. Nobumitsu Yokoi

Institute of Industrial Science (IIS), University of Tokyo, Japan

Abstract
Strongly compressible magnetohydrodynamic (MHD) turbulence is investigated with the aid of the multiple-scale direct-interaction approximation, a renormalised perturbation closure scheme for inhomogeneous turbulence at very high Reynolds numbers. Turbulence correlations in the mean-field equations are evaluated with analytical expressions of the turbulent transport coefficients. It is shown that, in addition to the usual solenoidal effects, genuine compressibility effects show up in the turbulence correlation expressions, which include the density variance effects in the turbulent electromotive force, the compressive cross-helicity effects in the turbulent mass and energy fluxes, etc. Turbulence modelling based on the theoretical results is also presented. Some possible applications to shock–turbulence interaction in the context of dynamo and magnetic reconnection are discussed.

References

– Yokoi, N. “Cross helicity and related dynamo,” Geophys. Astrophys. Fluid Dyn. 110, 114-184

(2013) doi.org/10.1080/03091929.2012.754022

– Yokoi, N. “Electromotive force in strongly compressible magnetohydrodynamic turbulence,” J.

Plasma Phys. 84, 1-26 (2018) doi:10.1017/S0022377818000727

Area della Ricerca di Roma 2 – Tor Vergata – IAPS

Via Fosso del Cavaliere, 100

00133 Roma

CONSIGLIO NAZIONALE DELLE RICERCHE - Area della Ricerca di Roma 2 - Tor Vergata Via del Fosso del Cavaliere, 100 - 00133 Roma