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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2508.12465 |
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| _version_ | 1866916978516557824 |
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| author | Getling, Alexander V. Kosovichev, Alexander G. |
| author_facet | Getling, Alexander V. Kosovichev, Alexander G. |
| contents | We use subsurface-flow velocity maps inferred by time--distance helioseismology from Doppler measurements with the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO) to investigate variations of large-scale convection during Solar Cycles 24 and 25 in the 19-Mm-deep layer. The spatial power spectra of the horizontal-flow divergence reveal well-defined characteristic scales of solar supergranulation in the upper 4 Mm layer, while the giant-cell scale is prominent below levels of d ~ 8 Mm. We find that the characteristic scales of supergranulation remain stable while the giant scales increase during the periods of the 11-year activity cycle maxima. The power of the giant-cell scales increases with the enhancement of solar activity. This may be due to large-scale flows around active regions and, presumably, solar-cycle variations of the convection-zone stratification. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_12465 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Activity-Cycle Variations of Convection Scales in Subsurface Layers of the Sun Getling, Alexander V. Kosovichev, Alexander G. Solar and Stellar Astrophysics We use subsurface-flow velocity maps inferred by time--distance helioseismology from Doppler measurements with the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO) to investigate variations of large-scale convection during Solar Cycles 24 and 25 in the 19-Mm-deep layer. The spatial power spectra of the horizontal-flow divergence reveal well-defined characteristic scales of solar supergranulation in the upper 4 Mm layer, while the giant-cell scale is prominent below levels of d ~ 8 Mm. We find that the characteristic scales of supergranulation remain stable while the giant scales increase during the periods of the 11-year activity cycle maxima. The power of the giant-cell scales increases with the enhancement of solar activity. This may be due to large-scale flows around active regions and, presumably, solar-cycle variations of the convection-zone stratification. |
| title | Activity-Cycle Variations of Convection Scales in Subsurface Layers of the Sun |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2508.12465 |