TY - JOUR
T1 - Supergranular-scale solar convection not explained by mixing-length theory
AU - Hanson, Chris S.
AU - Bharati Das, Srijan
AU - Mani, Prasad
AU - Hanasoge, Shravan
AU - Sreenivasan, Katepalli R.
N1 - Publisher Copyright:
© The Author(s), under exclusive licence to Springer Nature Limited 2024.
PY - 2024/9
Y1 - 2024/9
N2 - Supergranules, which are solar flow features with a lateral scale of 30,000–40,000 km and a lifetime of ~24 h, form a prominent component of the Sun’s convective spectrum. However, their internal flows, which can be probed only by helioseismology, are not well understood. We analyse dopplergrams recorded by the Solar Dynamics Observatory satellite to identify and characterize ~23,000 supergranules. We find that the vertical flows peak at a depth of ~10,000 km, and remain invariant over the full range of lateral supergranular scales, contrary to numerical predictions. We also infer that, within the local seismic resolution (≳5,000 km), downflows are ~40% weaker than upflows, indicating an apparent mass-flux imbalance. This may imply that the descending flows also comprise plumes, which maintain the mass balance but are simply too small to be detected by seismic waves. These results challenge the widely used mixing-length description of solar convection.
AB - Supergranules, which are solar flow features with a lateral scale of 30,000–40,000 km and a lifetime of ~24 h, form a prominent component of the Sun’s convective spectrum. However, their internal flows, which can be probed only by helioseismology, are not well understood. We analyse dopplergrams recorded by the Solar Dynamics Observatory satellite to identify and characterize ~23,000 supergranules. We find that the vertical flows peak at a depth of ~10,000 km, and remain invariant over the full range of lateral supergranular scales, contrary to numerical predictions. We also infer that, within the local seismic resolution (≳5,000 km), downflows are ~40% weaker than upflows, indicating an apparent mass-flux imbalance. This may imply that the descending flows also comprise plumes, which maintain the mass balance but are simply too small to be detected by seismic waves. These results challenge the widely used mixing-length description of solar convection.
UR - http://www.scopus.com/inward/record.url?scp=85196819156&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85196819156&partnerID=8YFLogxK
U2 - 10.1038/s41550-024-02304-w
DO - 10.1038/s41550-024-02304-w
M3 - Article
AN - SCOPUS:85196819156
SN - 2397-3366
VL - 8
SP - 1088
EP - 1101
JO - Nature Astronomy
JF - Nature Astronomy
IS - 9
ER -