I. N. Kitiashvili, A. G. Kosovichev, N. N. Mansour, S. K. Lele, A. A. Wray
Investigation of turbulent properties of solar convection is extremely
important for understanding of the multi-scale dynamics observed on the solar
surface. In particular, recent high-resolution observations revealed ubiquitous
vortical structures, and numerical simulations demonstrated links between the
vortex tube dynamics and magnetic field organization, and also importance of
vortex tube interactions in the mechanism of acoustic wave excitation on the
Sun. In this paper we investigate mechanisms of formation of vortex tubes in
highly-turbulent convective flows near the solar surface by using realistic
radiative hydrodynamic LES simulations. Analysis of data, obtained by the
simulations, indicates two basic processes of the vortex tube formation: 1)
development of small-scale convective instability inside convective granules,
and 2) a Kelvin-Helmholtz type instability of shearing flows in intergranular
lanes. Our analysis shows that vortex stretching during these processes is a
primary source of generation of small-scale vorticity on the Sun.
View original:
http://arxiv.org/abs/1112.5925
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