Radial mixing in the outer Milky Way disc caused by an orbiting satellite |
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| Authors: | A C Quillen Ivan Minchev Joss Bland-Hawthorn Misha Haywood |
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| Institution: | NORDITA, AlbaNova University Center, Roslagstullsbacken 23, SE - 106 91 Stockholm, Sweden;Astronomy Department, Columbia University, New York 10027, USA;JILA, University of Colorado, Boulder, CO 80309-0440, USA |
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| Abstract: | The turbulent diffusion tensor describing the evolution of the mean concentration of a passive scalar is investigated for non-helically forced turbulence in the presence of rotation or a magnetic field. With rotation, the Coriolis force causes a sideways deflection of the flux of mean concentration. Within the magnetohydrodynamics approximation there is no analogous effect from the magnetic field because the effects on the flow do not depend on the sign of the field. Both rotation and magnetic fields tend to suppress turbulent transport, but this suppression is weaker in the direction along the magnetic field. Turbulent transport along the rotation axis is not strongly affected by rotation, except on shorter length-scales, i.e. when the scale of the variation of the mean field becomes comparable with the scale of the energy-carrying eddies. These results are discussed in the context of anisotropic convective energy transport in the Sun. |
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| Keywords: | hydrodynamics magnetic fields MHD turbulence |
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