Friday, December 30, 2011

1112.5925 (I. N. Kitiashvili et al.)

Vortex Tubes of Turbulent Solar Convection    [PDF]

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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