IFIBA   22255
INSTITUTO DE FISICA DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Scale interactions in magnetohydrodynamic turbulence
Autor/es:
P.D. MININNI
Revista:
ANNUAL REVIEW OF FLUID MECHANICS
Editorial:
ANNUAL REVIEWS
Referencias:
Año: 2011 vol. 43 p. 377 - 397
ISSN:
0066-4189
Resumen:
This article reviews recent studies of scale interactions in
magnetohydrodynamic turbulence. The present-day increase of computing
power, which allows for the exploration of different configurations of
turbulence in conducting flows, and the development of shell-to-shell
transfer functions, has led to detailed studies of interactions between
the velocity and the magnetic field and between scales. In particular,
processes such as induction and dynamo action, the damping of velocity
fluctuations by the Lorentz force, and the development of anisotropies
can be characterized at different scales. In this context we consider
three different configurations often studied in the literature:
mechanically forced turbulence, freely decaying turbulence, and
turbulence in the presence of a uniform magnetic field. Each
configuration is of interest for different geophysical and
astrophysical applications. Local and nonlocal transfers are discussed
for each case. Whereas the transfer between scales of solely kinetic or
solely magnetic energy is local, transfers between kinetic and magnetic
fields are observed to be local or nonlocal depending on the
configuration. Scale interactions in the cascade of magnetic helicity
are also reviewed. Based on the results, the validity of several usual
assumptions in hydrodynamic turbulence, such as isotropy of the small
scales or universality, is discussed.