Open AccessEkman Layers and the Damping of Inertialr‐Modes in a Spherical Shell: Application to Neutron Stars
Author(s) -
M. Rieutord
Publication year - 2001
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/319705
Subject(s) - physics , neutron star , inertial wave , ekman number , dissipation , inertial frame of reference , mechanics , classical mechanics , rotation (mathematics) , instability , ekman transport , gravitation , ekman layer , compressibility , stars , boundary layer , flow (mathematics) , astrophysics , geometry , wave propagation , optics , thermodynamics , oceanography , upwelling , geology , mechanical wave , longitudinal wave , mathematics
Recently, eigenmodes of rotating fluids, namely inertial modes, have receivedmuch attention in relation to their destabilization when coupled togravitational radiation within neutron stars. However, these modes have beenknown for a long time by fluid dynamicists. We give a short account of theirhistory and review our present understanding of their properties. Consideringthe case of a spherical container, we then give the exact solution of theboundary (Ekman) layer flow associated with inertial r-modes and show thatprevious estimations all underestimated the dissipation by these layers. Wealso show that the presence of an inner core has little influence on thisdissipation. As a conclusion, we compute the window of instability in theTemperature/rotation plane for a crusted neutron star when it is modeled by anincompressible fluid.Comment: 7 pages, 2 figures, revised version to appear in ApJ, March 1
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