1. Solar Magneto-Convection: Structure & Dynamics Robert Stein - Mich. State Univ. Aake Nordlund - NBIfAFG

2. METHOD Solve conservation equations for: mass, momentum, internal energy & induction equation for vector potential Radiative heating/cooling -- solve Feautrier transfer equation, LTE, 4 opacity bins, 1 vertical & 4 slanted rays EOS includes ionization, excitation Simulation domain: T min - 2.5 Mm below surface, 6x6 Mm horizontally

3. METHOD

4. Conservation Equations Mass Momentum Energy Magnetic Flux

5. Radiation Transfer LTE Non-gray Formal Solution Calculate J - B by integrating Feautrier equations along one vertical and 4 slanted rays through each grid point on the surface. Produces low entropy plasma whose buoyancy work drives convection

6. 5 Rays Through Each Surface Grid Point Interpolate source function to rays at each height

7. Opacity is binned, according to its magnitude, into 4 bins.

8. Solve Transfer Equation for each bin i

9. MAGNETO- CONVECTION SIMULATIONS

10. 3D granulation (movie by Mats Carlsson)

11. B Swept to Cell Boundaries

12. Boundary Conditions Magnetic structure depends on boundary conditions 1)Inflows at bottom advect horizontal field in 2)At bottom: boundary magnetic field vertical At top: B tends toward potential

13. Magnetic Field Lines - fed horizontally

14. Magnetic Field Lines - initially vertical

15. Flux Emergence & Disappearance 12 34 Emerging flux Disappearing flux

17. G-band: Center to Limb (see poster II:9)

18. G-band Bright Points = large B, but some large B dark

19. G-band image & magnetic field contours (-.3,1,2 kG)

20. Magnetic Field & Velocity (@ surface)

21. Magnetic Field & Velocity High velocity sheets at edges of flux concentration

22. Temperature + B contours (1, 2, 3, kG)

23. Temperature & Velocity

24. Magnetic Field & Velocity

25. Temperature & Magnetic Field (contours 1, 2 kG)

26. Temperature & Velocity

27. Temperature Gradients largest next to magnetic concentrations

28. Magnetic concentrations: cool, low  low opacity. Towards limb, radiation emerges from hot granule walls behind. On optical depth scale, magnetic concentrations are hot, contrast increases with opacity

29. Micropore Formation Small granule is squeezed out of existence Magnetic flux moves into location of previous granule

30. The End