Inertial waves near corotation in three-dimensional hydrodynamical discs

Journal article

This paper concerns the interaction between non-axisymmetric inertial waves and their corotation resonances in a hydrodynamical disc. Inertial waves are of interest because they can localize in resonant cavities circumscribed by Lindblad radii and, as a consequence, can exhibit discrete oscillation frequencies that may be observed. It is often hypothesized that these trapped eigenmodes are affiliated with the poorly understood quasi-periodic oscillation phenomenon. We demonstrate that a large class of non-axisymmetric three-dimensional (3D) inertial waves cannot manifest as trapped normal modes. This class includes any inertial wave whose resonant cavity contains a corotation singularity. Instead, these 'singular' modes constitute a continuous spectrum and, as an ensemble, are convected with the flow, giving rise to shearing waves. Finally, we present a simple demonstration of how the corotation singularity stabilizes 3D perturbations in a slender torus. © 2009 RAS.

Authors: Latter, H; Balbus, S

• Publication status: Published
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 399
• Issue: 2
• Pages: 1058-1073
• Publication date: 2009-10-21
• DOI: 10.1111/j.1365-2966.2009.15350.x
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: instabilities; waves; hydrodynamics; accretion discs; accretion