Physical Origin of Differences among various Measures of Solar Meridional Circulation
arXiv:1008.2772 · doi:10.1088/0004-637X/722/1/774
Abstract
We show that systematic differences between surface Doppler and magnetic element tracking measures of solar meridional flow can be explained by the effects of surface turbulent magnetic diffusion. Feature-tracking speeds are lower than plasma speeds in low and mid-latitudes, because magnetic diffusion opposes poleward plasma flow in low-latitudes whereas it adds to plasma flow at high latitudes. Flux transport dynamo models must input plasma flow; the model-outputs yield estimates of the surface magnetic feature tracking speed. We demonstrate that the differences between plasma speed and magnetic pattern speed in a flux-transport dynamo are consistent with the observed difference between these speeds.
To appear in ApJ
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- Surface Flux Transport on the Sun
- Measurements of Solar Differential Rotation and Meridional Circulation from Tracking of Photospheric Magnetic Features
- Parameter optimization for surface flux transport models
- Polar Field Puzzle: Solutions from Flux-Transport Dynamo and Surface Transport Models
- Effect of Magnetic Field Strength on Solar Differential Rotation and Meridional Circulation
- Helioseismic inversion to infer depth profile of solar meridional flow using spherical Born kernels
- Improved Measurements of the Sun's Meridional Flow and Torsional Oscillation from Correlation tracking on MDI \& HMI magnetograms
- Comparison of solar activity proxies: eigen vectors versus averaged sunspot numbers