Nonlinear multi-mode coupling of the solar gravity modes in a rotationally split multiplet
This dissertation explores some of the nonlinear properties of gravity-mode oscillations in the solar interior. In particular, it is concerned with the interactions amongst the nonradial modes of a single rotationally split multiplet. It investigates the multi-mode coupling of a larger number (typically about 20) of the modes in a multiplet. Many internal resonances occur in a given problem, and the effects occur at third order. Motivation for this analysis arises both from general theoretical interest and from observed properties of the Sun that have recently become available. Observations of solar gravity-mode oscillation eigenfrequencies and eigenfunctions obtained at the Santa Catalina Laboratory for Experimental Relativity by Astrometry (SCLERA) show strong evidence of nonlinear effects. This dissertation provides a general theoretical framework for investigating many problems of second- and third-order mode coupling in stellar systems. A multiple-scale perturbation technique is used. The theory provides a means to infer the core amplitudes of the gravity-modes exhibiting the nonlinear behavior in the SCLERA data. This is a significant accomplishment because it bypasses the traditional extrapolation of measured surface amplitudes into the interior, which is a questionable procedure, in part because of the uncertainity regarding the surface boundary conditions in the Sun. It is found that the relative radial displacement of these oscillations, {delta}r/r, has a typical maximum amplitude in the interior of (6 {times} 10{sup {minus}4} {+-} 30%). The maximum of the relative Lagrangian temperature variation, {delta}T/T, is (7 {times} 10{sup {minus}5}). The potential implications of such interior amplitude determinations are briefly discusses.
- Research Organization:
- Arizona Univ., Tucson, AZ (USA)
- OSTI ID:
- 6597570
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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