Helioseismology challenges models of solar convection

TL;DR

This paper uses helioseismic observations to set empirical limits on solar convection velocities, revealing significant discrepancies with existing hydrodynamic models of the Sun's outer convection zone.

Contribution

It provides the first stringent observational constraints on large-scale solar convective velocities, challenging current theoretical models.

Findings

Observed convective velocities are much lower than model predictions.

Empirical upper limits significantly restrict the amplitude of solar convection.

Results suggest a need to revise models of solar turbulent convection.

Abstract

Convection is the mechanism by which energy is transported through the outermost 30% of the Sun. Solar turbulent convection is notoriously difficult to model across the entire convection zone where the density spans many orders of magnitude. In this issue of PNAS, Hanasoge et al. (2012) employ recent helioseismic observations to derive stringent empirical constraints on the amplitude of large-scale convective velocities in the solar interior. They report an upper limit that is far smaller than predicted by a popular hydrodynamic numerical simulation.