Absorption of Waves in Accretion Disks. I. Resonance at the Radius Where the Wave Frequency Matches the Vertical Brunt-Vaisala Frequency
The propagation properties of internal gravity waves in a rotating torus are considered. The oscillations are assumed to be axisymmetric and adiabatic. In the short-wavelength limit in the vertical direction, the gravity waves whose frequency is omega are confined in the region in which [omega -N(r)][omega -kappa (r)]<0 holds, where N and kappa are the Brunt-Vaisala frequency for vertical displacement and the epicyclic frequency, respectively, and r is the radial coordinate. We find that the gravity waves are resonantly absorbed to heat the plasma at the radius where omega equals N(r). This radius is probably located in the innermost region of the torus, where most X-rays are emitted. Some implications of this result, with respect to quasi-periodic oscillations observed from low-mass X-ray binaries, are briefly discussed.
Publications of the Astronomical Society of Japan
- Pub Date:
- October 1995
- ACCRETION DISKS;
- X-RAYS: BINARIES