Post on 20-Dec-2015
transcript
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