Solar inertial modes: Observations, identification, and diagnostic promise
| Autor: | Damien Fournier, Zhi-Chao Liang, Yuto Bekki, Robert H. Cameron, Bastian Proxauf, Cilia Damiani, Laura Hyest, Aaron C. Birch, B. Lekshmi, Allan Sacha Brun, Laurent Gizon, Richard S. Bogart, Kiran Jain |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Inertial frame of reference
FOS: Physical sciences Astrophysics 01 natural sciences Spherical shell Physics::Fluid Dynamics Normal mode 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Helioseismology 010306 general physics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Physics::Atmospheric and Oceanic Physics Physics Toroid Astronomy and Astrophysics Mechanics Convection zone Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Physics::Space Physics Solar rotation Restoring force Astrophysics::Earth and Planetary Astrophysics |
| Popis: | The oscillations of a slowly rotating star have long been classified into spheroidal and toroidal modes. The spheroidal modes include the well-known 5-min acoustic modes used in helioseismology. Here we report observations of the Sun's toroidal modes, for which the restoring force is the Coriolis force and whose periods are on the order of the solar rotation period. By comparing the observations with the normal modes of a differentially rotating spherical shell, we are able to identify many of the observed modes. These are the high-latitude inertial modes, the critical-latitude inertial modes, and the equatorial Rossby modes. In the model, the high-latitude and critical-latitude modes have maximum kinetic energy density at the base of the convection zone, and the high-latitude modes are baroclinically unstable due to the latitudinal entropy gradient. As a first application of inertial-mode helioseismology, we constrain the superadiabaticity and the turbulent viscosity in the deep convection zone. Forthcoming article, Astronomy and Astrophysics |
| Databáze: | OpenAIRE |
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