Europhys. Lett, 43 (5), pp. 516-521 (1998)
Determination of anomalous exponents
of structure functions
H. Politano 1, A. Pouquet 1 and V. Carbone 2
1 Laboratoire G.D. Cassini, CNRS UMR 6529, OCA Observatoire de Nice
B.P. 4229, 06304 Nice Cedex 04, France
2 Dipartimento di Fisica, Università della Calabria
87036 Roges di Rende, Cosenza, Italy
(received 23 February 1998; accepted in final form 14 July 1998)
PACS. 47.27Jv - High-Reynolds-number turbulence.
PACS. 47.27Gs - Isotropic turbulence; homogeneous turbulence.
PACS. 47.65 - Magnetohydrodynamics and electrohydrodynamics.
We determine numerically in two space dimensions the anomalous exponents of structure functions of the velocity , the magnetic field and the Elsässer variables up to order eight. To that effect, we make use of new exact relationships derived recently for mixed third-order correlators. These exponents are compared to existing models of intermittency for either neutral or MHD flows, none of which seem to apply, possibly indicative of a more complex behavior for MHD flows than for neutral fluids.