Volume 425, Number 2, October II 2004
|Page(s)||385 - 393|
|Published online||21 September 2004|
Accretion disk instability revisited
Transient dynamics of rotating shear flow
Department of Astronomy, Columbia University, New York, NY, USA e-mail: firstname.lastname@example.org Department of Physics and Astronomy, Arizona State University, Tempe, Arizona, USA
Accepted: 28 June 2004
Accretion disk flow in a local Cartesian (or “shearing box”) approximation is examined for viscous three-dimensional linear disturbances. Eigenvalue computations predict that the flow is asymptotically stable unless the rotation number falls in the range , in agreement with predictions of inviscid theory; Keplerian flow () is accordingly stable. Analysis of non-modal disturbances predicts large transient amplification factors, implying that the flow, although asymptotically stable, may be transiently unstable. Strong rotation, including Keplerian, two-dimensionalizes the system: the largest growth factors are found for disturbances which are uniform along the direction of the rotation axis and amplification occurs via the Orr mechanism, as in 2D shear flow. Amplification factors scale as , implying very strong growth in actual disks. The implications of transient instability of rotating shear on disk turbulence are discussed.
Key words: accretion, accretion disks / instabilities / turbulence / hydrodynamics
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.