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This article explores the current state and future directions of convection modeling, with a focus on its implications for HMI (Helioseismic and Magnetic Imager). It discusses various objectives, including understanding the tachocline and near-surface layers, as well as incorporating convection explicitly in 3D Dynamo simulations. The article also highlights how HMI can contribute to these goals by providing insights into various dynamics such as meridional circulation, flux-transport dynamos, coherent structures at low latitudes, and magnetic helicity flux through the photosphere.
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Global ConvectionModeling(where are we heading and how does this impact HMI?) Mark Miesch HAO/NCAR, JILA/CU (Sacha Brun, Juri Toomre, Matt Browning, Marc DeRosa, Ben Brown) Feb, 2006
Objective 1Understand what’s going on in the tachocline and incorporate it into our models • Penetrative convection with shear & pumping • Magnetic buoyancy instabilities & flux tube formation • Magneto-shear instabilities (global & local) • Gravity wave generation, propagation & transport • Tachocline confinement • Thermal coupling to convection zone
Objective 2Understand and model the near-surface layers • Couple to surface convection simulations • Compare with local helioseismic inversions • Near-surface shear layer • Magnetic helicity flux through the photosphere and conseqences for dynamo action
Objective 33D Dynamo simulations spanning the solar activity cycle which incorporate convection explicitly • Narrow the gap with mean-field dynamo models • Subgrid-scale modeling • Coupling to the top & bottom of the CZ (Objectives 1 & 2)
How can HMI help? • Meridional Circulation • Are flux-transport dynamos on the right track? • North-South lanes of downflow/horizontal convergence • Are these really the dominant coherent structures at low latitudes? • Latitudinal entropy/temperature variations • Is the solar rotation really in thermal wind balance? • Velocity/thermal/magnetic correlations • Invaluable insight into the underlying dynamics • Non-axisymmetric patterns in flux emergence (esp. m=1) • Indicative of tachocline instabilities? • Jets & Oscillations • Could reflect instabilities, waves, stratified turbulence, etc. • Magnetic helicity flux through the photosphere • May regulate dynamo action
How can HMI help? • Meridional Circulation • Are flux-transport dynamos on the right track? • North-South lanes of downflow/horizontal convergence • Are these really the dominant coherent structures at low latitudes? • Latitudinal entropy/temperature variations • Is the solar rotation really in thermal wind balance? • Velocity/thermal/magnetic correlations • Invaluable insight into the underlying dynamics • Non-axisymmetric patterns in flux emergence (esp. m=1) • Indicative of tachocline instabilities? • Jets & Oscillations • Could reflect instabilities, waves, stratified turbulence, etc. • Magnetic helicity flux through the photosphere • May regulate dynamo action