The linear theory of tidally excited spiral density waves: application to CV and circumplanetary disks

Abstract

We revisit linear tidal excitation of spiral density waves in the disks of cataclysmic variables (CVs), focusing on scalings with orbital Mach number in order to bridge the gap between numerical simulations and real systems. If an inner Lindblad resonance (ILR) lies within the disk, ingoing waves are robustly excited, and the angular-momentum flux they carry is independent of Mach number. But in most CVs, the ILR lies outside the disk. The wave flux and its scaling with Mach number are then very sensitive to conditions near the disk edge. If the temperature and sound speed vanish there, excitation tends to be exponentially suppressed. If the Mach number remains finite in the outer parts but the radial and vertical density scale lengths become comparable due to subkeplerian rotation, resonance can occur with acoustic-cutoff and stratification frequencies. These previously neglected resonances excite waves, but the Mach-number scaling remains very steep if the radial scale length decreases gradually. The scaling can be less strong - algebraic rather than exponential - if there are sharp changes in surface density at finite sound speed. Shocks excited by streamline-crossing or by the impact of the stream from the companion are unlikely to be important for the angular-momentum budget, at least in quiescence. Our results may also apply to circumplanetary disks, where Mach numbers are likely lower than in CVs.

arXiv comment15 pages, 4 figures

References in corpus (10)

• Three-dimensional waves generated at Lindblad resonances in thermally stratified disks
• The Kepler light curves of V1504 Cygni and V344 Lyrae: A study of the Outburst Properties
• Viscosity Mechanisms in Accretion Disks
• Shock-driven Accretion in Circumplanetary Disks: Observables and Satellite Formation
• Tidally-Driven Transport in Accretion Disks in Close Binary Systems
• Tidally distorted accretion discs in binary stars
• Accretion Disc Evolution in DW Ursae Majoris: A Photometric Study
• Tracing the spiral arms in IP Pegasi
• SOAR observations of the high-viscosity accretion disc of the dwarf nova V4140 Sagitarii in quiescence and in outburst
• Spiral structures and temperature distribution in the quiescent accretion disc of the cataclysmic binary V2051 Ophiuchi

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• A review of the disc instability model for dwarf novae, soft X-ray transients and related objects
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