Wave propagation in semi-convective regions of giant planets
| Autor: | C. M. Pontin, Q. André, Rainer Hollerbach, Adrian J. Barker, Stéphane Mathis |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
Convection Earth and Planetary Astrophysics (astro-ph.EP) 010504 meteorology & atmospheric sciences Wave propagation Fluid Dynamics (physics.flu-dyn) FOS: Physical sciences Astronomy and Astrophysics Mechanics Physics - Fluid Dynamics Internal wave Dissipation 01 natural sciences Asteroseismology Core (optical fiber) Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Planet 0103 physical sciences Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences Envelope (waves) Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society |
| ISSN: | 0035-8711 |
| DOI: | 10.48550/arxiv.2003.02595 |
| Popis: | Recent observations of Jupiter and Saturn suggest that heavy elements may be diluted in the gaseous envelope, providing a compositional gradient that could stabilise ordinary convection and produce a stably-stratified layer near the core of these planets. This region could consist of semi-convective layers with a staircase-like density profile, which have multiple convective zones separated by thin stably-stratified interfaces, as a result of double-diffusive convection. These layers could have important effects on wave propagation and tidal dissipation that have not been fully explored. We analyse the effects of these layers on the propagation and transmission of internal waves within giant planets, extending prior work in a local Cartesian model. We adopt a simplified global Boussinesq planetary model in which we explore the internal waves in a non-rotating spherical body. We begin by studying the free modes of a region containing semi-convective layers. We then analyse the transmission of internal waves through such a region. The free modes depend strongly on the staircase properties, and consist of modes with both internal and interfacial gravity wave-like behaviour. We determine the frequency shifts of these waves as a function of the number of steps to explore their potential to probe planetary internal structures. We also find that wave transmission is strongly affected by the presence of a staircase. Very large-wavelength waves are transmitted efficiently, but small-scale waves are only transmitted if they are resonant with one of the free modes. The effective size of the core is therefore larger for non-resonant modes. Comment: 19 pages, 14 figures, accepted for publication in MNRAS on 2nd March 2020 |
| Databáze: | OpenAIRE |
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