Convection and p-modes.
Abstract
An introductory overview of the qualitative properties of convection and p modes in solar type stars is followed by a discussion of how to obtain a meaningful separation between "wave-motion" and "convection" in a strongly inhomogeneous medium. For radial waves, a natural separation is obtained by using certain weighted averages, in a "pseudo-Lagrangian" coordinate system in which there is no net vertical mass flux. Three principal influences of the convection on the wave modes are identified: Frequency shifts due to coherent perturbations in phase with "restoring force" terms in the wave equations, linear damping or growth due to coherent perturbations 90 degrees out of phase with restoring force terms, and stochastic excitation due to incoherent perturbations of the wave equations. In addition, convection influences p-modes by cavity changes: i.e., changes of the size of the resonant cavity due to changes in the mean structure. Numerical illustrations of these effects are given, using results from supercomputer simulations of the interaction of solar convection with p-modes.
- Publication:
-
Diagnostics of Solar Oscillation Observations
- Pub Date:
- 1991
- Bibcode:
- 1991dsoo.conf...37N