IFIBA   22255
INSTITUTO DE FISICA DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Lack of universality in decaying magnetohydrodynamic turbulence
Autor/es:
E. LEE; M.E. BRACHET; A. POUQUET; P.D. MININNI; D. ROSENBERG
Revista:
PHYSICAL REVIEW E
Editorial:
AMER PHYSICAL SOC
Referencias:
Año: 2010 vol. 81 p. 163181 - 163189
ISSN:
1539-3755
Resumen:
Using computations of three-dimensional magnetohydrodynamic (MHD)
turbulence with a Taylor-Green flow, whose inherent time-independent
symmetries are implemented numerically, and in the absence of either a
forcing function or an imposed uniform magnetic field, we show that
three different inertial ranges for the energy spectrum may emerge for
three different initial magnetic fields, the selecting parameter being
the ratio of nonlinear eddy to Alfvén time. Equivalent computational
grids range from 1283 to 20483
points with a unit magnetic Prandtl number and a Taylor Reynolds number
of up to 1500 at the peak of dissipation. We also show a convergence of
our results with Reynolds number. Our study is consistent with previous
findings of a variety of energy spectra in MHD turbulence by studies
performed in the presence of both a forcing term with a given
correlation time and a strong, uniform magnetic field. However, in
contrast to the previous studies, here the ratio of characteristic time
scales can only be ascribed to the intrinsic nonlinear dynamics of the
paradigmatic flows under study.