A Linear Model for Inertial Modes in a Differentially Rotating Sun
Inertial wave modes in the Sun are of interest owing to their potential to reveal new insight into the solar interior. These predominantly retrograde-propagating modes in the solar subsurface appear to deviate from the thin-shell Rossby–Haurwitz model at high azimuthal orders. We present new measure...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad226c |
| _version_ | 1797223678782472192 |
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| author | Jishnu Bhattacharya Chris S. Hanson Shravan M. Hanasoge Katepalli R. Sreenivasan |
| author_facet | Jishnu Bhattacharya Chris S. Hanson Shravan M. Hanasoge Katepalli R. Sreenivasan |
| author_sort | Jishnu Bhattacharya |
| collection | DOAJ |
| description | Inertial wave modes in the Sun are of interest owing to their potential to reveal new insight into the solar interior. These predominantly retrograde-propagating modes in the solar subsurface appear to deviate from the thin-shell Rossby–Haurwitz model at high azimuthal orders. We present new measurements of sectoral inertial modes at m > 15 where the modes appear to become progressively less retrograde compared to the canonical Rossby–Haurwitz dispersion relation in a corotating frame. We use a spectral eigenvalue solver to compute the spectrum of solar inertial modes in the presence of differential rotation. Focussing specifically on equatorial Rossby modes, we find that the numerically obtained mode frequencies lie along distinct ridges, one of which lies strikingly close to the observed mode frequencies in the Sun. We also find that the n = 0 ridge is deflected strongly in the retrograde direction. This suggests that the solar measurements may not correspond to the fundamental n = 0 Rossby–Haurwitz solutions as was initially suspected, but to those for a higher n . The numerically obtained eigenfunctions also appear to sit deep within the convection zone—unlike those for the n = 0 modes—which differs substantially from solar measurements and complicates inference. |
| first_indexed | 2024-04-24T13:41:03Z |
| format | Article |
| id | doaj.art-d45e0c2be6b94087bae5770aa43ac8cc |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-04-24T13:41:03Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-d45e0c2be6b94087bae5770aa43ac8cc2024-04-04T08:44:38ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196515510.3847/1538-4357/ad226cA Linear Model for Inertial Modes in a Differentially Rotating SunJishnu Bhattacharya0https://orcid.org/0000-0001-6433-6038Chris S. Hanson1https://orcid.org/0000-0003-2536-9421Shravan M. Hanasoge2https://orcid.org/0000-0003-2896-1471Katepalli R. Sreenivasan3https://orcid.org/0000-0002-3943-6827Center for Space Science, New York University Abu Dhabi , Abu Dhabi, PO Box 129188, UAECenter for Astrophysics and Space Science, New York University Abu Dhabi , Abu Dhabi, PO Box 129188, UAECenter for Astrophysics and Space Science, New York University Abu Dhabi , Abu Dhabi, PO Box 129188, UAE; Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research , Mumbai—400005, IndiaCenter for Astrophysics and Space Science, New York University Abu Dhabi , Abu Dhabi, PO Box 129188, UAE; New York University , New York, NY 10012 USAInertial wave modes in the Sun are of interest owing to their potential to reveal new insight into the solar interior. These predominantly retrograde-propagating modes in the solar subsurface appear to deviate from the thin-shell Rossby–Haurwitz model at high azimuthal orders. We present new measurements of sectoral inertial modes at m > 15 where the modes appear to become progressively less retrograde compared to the canonical Rossby–Haurwitz dispersion relation in a corotating frame. We use a spectral eigenvalue solver to compute the spectrum of solar inertial modes in the presence of differential rotation. Focussing specifically on equatorial Rossby modes, we find that the numerically obtained mode frequencies lie along distinct ridges, one of which lies strikingly close to the observed mode frequencies in the Sun. We also find that the n = 0 ridge is deflected strongly in the retrograde direction. This suggests that the solar measurements may not correspond to the fundamental n = 0 Rossby–Haurwitz solutions as was initially suspected, but to those for a higher n . The numerically obtained eigenfunctions also appear to sit deep within the convection zone—unlike those for the n = 0 modes—which differs substantially from solar measurements and complicates inference.https://doi.org/10.3847/1538-4357/ad226cHelioseismologyThe SunComputational methodsHydrodynamics |
| spellingShingle | Jishnu Bhattacharya Chris S. Hanson Shravan M. Hanasoge Katepalli R. Sreenivasan A Linear Model for Inertial Modes in a Differentially Rotating Sun The Astrophysical Journal Helioseismology The Sun Computational methods Hydrodynamics |
| title | A Linear Model for Inertial Modes in a Differentially Rotating Sun |
| title_full | A Linear Model for Inertial Modes in a Differentially Rotating Sun |
| title_fullStr | A Linear Model for Inertial Modes in a Differentially Rotating Sun |
| title_full_unstemmed | A Linear Model for Inertial Modes in a Differentially Rotating Sun |
| title_short | A Linear Model for Inertial Modes in a Differentially Rotating Sun |
| title_sort | linear model for inertial modes in a differentially rotating sun |
| topic | Helioseismology The Sun Computational methods Hydrodynamics |
| url | https://doi.org/10.3847/1538-4357/ad226c |
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