Turbulence and its parameterization in accretion discs
Turbulence and its parameterization in accretion discs
复制标题
吸积盘中的湍流及其参数化
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Brandenburg
中科院分区：
文献类型：
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作者：
A. Brandenburg
Accretion disc turbulence is investigated in the framework of the shearing box approximation. The turbulence is either driven by the magneto-rotational instability or, in the non-magnetic case, by an explicit and artificial forcing term in the momentum equation. Unlike the magnetic case, where most of the dissipation occurs in the disc corona, in the forced hydrodynamic case most of the dissipation occurs near the midplane. In the hydrodynamic case evidence is presented for the stochastic excitation of epicycles. When the vertical and radial epicyclic frequencies are different (modeling the properties around rotating black holes), the beat frequency between these two frequencies appear to show up as a peak in the temporal power spectrum in some cases. Finally, the full turbulent resistivity tensor is determined and it is found that, if the turbulence is driven by a forcing term, the signs of its off-diagonal components are such that this effect would not be capable of dynamo action by the shear–current effect. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
