1. Issues and Needs in Solar Modeling James A. Klimchuk Rebekah M. Evans NASA/GSFC

2. thermal cond. heating radiation Modeling the Magnetically-Closed Corona: Pressure Boundary Conditions = 0 Static equilibrium: = 0

3. Modeling the Magnetically-Closed Corona: Pressure Boundary Conditions Approximate solution (scaling law): L (field line length) is set by the photospheric mag. flux distribution. Q (heating rate) is specified. P (pressure) is a free parameter that cannot be specified. Doing so over constrains the solution. The correct approach is to add a simple chromosphere (several scale heights thick), to the bottom of each leg. P  Q 6/7 L 5/7

4. Modeling the Magnetically-Closed Corona: Pressure Boundary Conditions z Log P

5. Modeling the Magnetically-Closed Corona: Pressure Boundary Conditions z Log P P  Q 6/7 L 5/7

6. BATS-R-US Results Temperature Pressure Velocity t = 8380 s

7. Temperature Pressure Velocity Heating Radiation Conduction Enthalpy 0 0 Energy Sources and Sinks

8. Actual ~ 10,000 s Conservation of Mass Issue Divergence of Mas Flux 0

9. Conservation of Energy Issue Actual ~ + 100,000 s Energy Sources and Sinks 0

10. Needs Immediate: Ability to plot field lines (ability to write output files that TecPlot can read) Near term: Understand/correct the apparent conservation of mass and energy issues Ability to impose a simple shear flow and have the system respond correctly Long term: Ability to treat partially-ionized plasmas o electrons, protons, neutrals are all major species o various approaches, including single partially-ionized hydrogen fluid o Pederson resistivity o Ion-neutral drag (ambipolar diffusion)