Forward Modeling Helioseismic Signatures of One- and Two-cell Meridional Circulation

Abstract

Using a 3D global solver of the linearized Euler equations, we model acoustic oscillations over background velocity flow fields of single-cell meridional circulation with deep and shallow return flows as well as double-cell meridional circulation with strong and weak reversals. The velocities are generated using a mean-field hydrodynamic and dynamo model -- moving through the regimes with minimal parameter changes; counter-rotation near the base of the tachocline is induced by sign inversion of the non-diffusive action of turbulent Reynolds stresses ($\Lambda$-effect) due to the radial inhomogeneity of the Coriolis number. By mimicking the stochastic excitation of resonant modes in the convective interior, we simulate realization noise present in solar observations. Using deep-focusing to analyze differences in travel-time signatures between the four regimes, as well as comparing to solar observations, we show that current helioseismology techniques may offer important insights about the location and strength of the return flow, however, that it may not currently be possible to definitively distinguish between profiles of single-cell or double-cell meridional circulation.

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Cited by in corpus (4)

• Turbulent processes and mean-field dynamo
• The Extended Solar Cycle and Asymmetry of the Large-Scale Magnetic Field
• Implicit large eddy simulations of global solar convection: effects of numerical resolution in non-rotating and rotating cases
• Constraining Global Solar Models through Helioseismic Analysis