1. Multifluid Simulations of the Magnetosphere

2. Final Equations Equations are not conservative except for the sum over all species Momentum is transferred from one species to another as the magnetic field changes direction

3. Perp and parallel ½ ® @ ~ u ® ; ? @ t = ½ ® f ( @ ~ u ® @ t ) ? ¡ ~ u ¢ @ @ t ( ~ B ~ B B 2 ) g ½ ® @ ~ u ® ; k @ t = ½ ® f ( @ ~ u ® @ t ) k + ~ u ¢ @ @ t ( ~ B ~ B B 2 ) g

4. Research ( not proof of principle ) calculations Demonstration of uses of multi-fluid MHD Demonstration of uses of multi-fluid MHD Solar wind entry to the magnetotail Solar wind entry to the magnetotail Simulated ionospheric oxygen outflow Simulated ionospheric oxygen outflow Global cloud Global cloud Coupled polar wind Coupled polar wind Post cusp plume Post cusp plume

5. Plasma entry (Peter Damiano) Solar wind is split into two fluids Solar wind is split into two fluids Plasma on the grid to start is fluid A Plasma on the grid to start is fluid A Solar wind plasma is now part fluid A and part fluidB Solar wind plasma is now part fluid A and part fluidB Both have identical properties and sum to a standard solar wind Both have identical properties and sum to a standard solar wind Multi-fluid provides a way of marking plasma with a tracer dye Multi-fluid provides a way of marking plasma with a tracer dye Similar to using test particles, except dye fluid responds exactly the same way the fluid calculations does Similar to using test particles, except dye fluid responds exactly the same way the fluid calculations does

7. Multi-fluid vs LFM Density in false color; Bz = 0 contour

8. Fluids inverted Calculations gradually diverge

9. Inflow is clear Inflow is clear Comes in from the flanks first Comes in from the flanks first K-H ? K-H ? Numerical issues need to be quantified Numerical issues need to be quantified Fluid element traciing doesn’t seem to exactly follow finger development Fluid element traciing doesn’t seem to exactly follow finger development

10. Ionospheric Outflow Robert Winglee has pioneered modeling in this direction (e.g. JGR 107, A9, 1237,2002) Robert Winglee has pioneered modeling in this direction (e.g. JGR 107, A9, 1237,2002) Model has no ionosphere, simply a resistive zone around the Earth Model has no ionosphere, simply a resistive zone around the Earth Models outflow by placing high density ( ~400/cc ) at inner boundary, relatively cold (0.1- 60eV) Models outflow by placing high density ( ~400/cc ) at inner boundary, relatively cold (0.1- 60eV) Outflow controlled by “centrifugal acceleration” depending on solar wind IMF Outflow controlled by “centrifugal acceleration” depending on solar wind IMF Produces hot, keV oxygen Produces hot, keV oxygen Outflow rates roughly consistent with observations Outflow rates roughly consistent with observations Strong reduction in CPCP for strong outflow Strong reduction in CPCP for strong outflow

11. O plume during a substorm Mike Wiltberger, HAO/NCAR O plume during a substorm Mike Wiltberger, HAO/NCAR Standard solar wind Standard solar wind 5 nT S IMF, n = 5/cc, v SW =400 km/s 5 nT S IMF, n = 5/cc, v SW =400 km/s About an hour after southward turning there is a substorm About an hour after southward turning there is a substorm Region just poleward of cusp and insert arbitrary outflow Region just poleward of cusp and insert arbitrary outflow Flux =10 9 / cm 2 Flux =10 9 / cm 2 Velocity = 40 km/s Velocity = 40 km/s Thermal speed = 10 km/s Thermal speed = 10 km/s

12. Oxygen outflow from cleft

13. Substorm behavior with and without outflow

14. Substorm behavior

15. Outflow clearly has a strong effect on the tail dynamics Outflow clearly has a strong effect on the tail dynamics Brings x-line in Brings x-line in Recurrent substorms? Recurrent substorms?

16. Centrifugal acceleration Katie Garcia has been investigating the relative importance of centrifugal acceleration in oxygen outflow Katie Garcia has been investigating the relative importance of centrifugal acceleration in oxygen outflow Uses the empirical Akebono model to define outflow with a thermal plasma. Uses the empirical Akebono model to define outflow with a thermal plasma. ½ ® D ~ u k D t = ½ ® ~ u ® ; ? ¢ D ^ b D t ¡ ^ b ¢ r P

17. Field-aligned bulk acceleration Yellow: magnetic field lines Yellow: magnetic field lines Green: streamlines Green: streamlines a pressure a centrifugal nv || B log(a p /a c )

18. Acceleration Along a Streamline log(a c /a p ) log(a c /a p ) a pressure a centrifugal v [km/s] a [km/s 2 ] a out a in v out v in Black lines: values along streamlines Orange lines: average of 30 minutes of streamlines (avg of black lines)

19. Centrifugal acceleration seems to be less important than pressure in accelerating outflow Centrifugal acceleration seems to be less important than pressure in accelerating outflow Even without strong centrifugal acceleration relatively high sppeds can be dd\eveloped Even without strong centrifugal acceleration relatively high sppeds can be dd\eveloped

20. Future work Continuing work shown today Continuing work shown today Plasmasphere Plasmasphere Bring on-line MPI multifluid Bring on-line MPI multifluid