1. Supergranulation-Scale Simulations of Solar Convection Robert Stein, Michigan State University, USA Aake Nordlund, Astronomical Observatory, NBIfAFG, Denmark David Benson, Michigan State University, USA

2. Computational Domain 48Mm x 48Mm x 20Mm 500 3 grid points non-uniform vertical mesh –12km @ surface –70km @ bottom uniform horizontal mesh –100km horizontal resolution 48 Mm 20 Mm Computational Domain for the CFD Simulations of Solar Convection

3. Numerical Method Spatial differencing –6th-order f.d. –staggered Time advancement –3rd order Runga-Kutta Equation of state –tabular –including ionization –H, He + abundant elements Radiative transfer –3D, LTE –4 bin opacity distrib. fxn Quenching

4. Mean Atmosphere State Temperature, Density and Pressure

5. Mean Atmosphere State Ionization of H and He

6. -- 6.5 hr sequence (out of 50 hrs). Velocity in vertical plane

7. l to r --> top to bottom surface, 2, 4, 8, 12, 16 Mm Continuous scale change: granulates -> supergranules vertical velocity on horizontal planes (48 Mm wide)

8. Velocity spectrum no features besides granulation

9. Upflows at surface come from small area at bottom (left) Downflows at surface converge to supergranule boundaries (right)

11. Oscillation modes: k-  diagram

12. How to calculate the spectrum? Average power spectra (correct) or Average time sequence (incorrect) Artificial feature, Noisy

13. Simulation Data Is available –Full data sets ~ 200 Gb per hour solar time –Slices of Vxyz & T at selected depths ~ 2 Gb per hour solar time Contact: Bob Stein stein@pa.msu.edu

14. Solar Physics Post-Doc Dr. Robert Stein Michigan State University Simulate solar magneto-convection Apply to local helioseismology solarpostdoc@pa.msu.edu