Turbulence and its parameterization in accretion discs
نویسندگان
چکیده
منابع مشابه
Turbulence and its parameterization in accretion discs
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 dissipa...
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Local hydromagnetic simulations of accretion disc turbulence provide now the most convincing evidence that the origin of turbulence in discs could be the Balbus{Hawley magneto-rotational instability. The main results of such calculations are highlighted with particular emphasis on the generation of large scale magnetic elds. Comparison with mean-eld dynamo theory is made. This theory is then us...
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Local hydromagnetic simulations of accretion-disc turbulence currently provide the most convincing evidence that the origin of turbulence in discs could be the Balbus{ Hawley magnetorotational instability. The main results of such calculations are highlighted with particular emphasis on the generation of large-scale magnetic elds. Comparison with mean- eld dynamo theory is made. This theory ...
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Rapid accretion of cold intergalactic gas plays a crucial role in getting gas into galaxies. It has been suggested that this gas accretion proceeds along narrow streams that might also directly drive the turbulence in galactic gas, dynamical disturbances and bulge formation. In cosmological simulations, however, it is impossible to isolate and hence disentangle the effect of cold stream accreti...
متن کاملModelling magnetised accretion discs
Some recent results are reviewed that lead us now to believe that accretion discs are basically always magnetised. The main components are Balbus-Hawley and Parker instabilities on the one hand and a dynamo process on the other. A mechanical model for the Balbus-Hawley instability is presented and analysed quantitatively. Three-dimensional simulations are discussed, especially the resulting mag...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 2005
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.200510414