Multi-Fluid/Particle Treatment of Magnetospheric-Ionospheric Coupling During Substorms and Storms

1. Multi-Fluid/Particle Treatment of Magnetospheric-Ionospheric CouplingDuring Substorms and Storms R. M. Winglee

2. Strong Heavy Ion Ionospheric Outflows observed during active periods • Substantial Asymmetries that provide key insight during active periods • Multi-Fluid Equations ideal substorm • Particle acceleration associated with boundary layers • Magnetic reconnection & current sheet acceleration • Influence of heavy ions on the global dynamics • Application to the Storm of April 17, 2003

3. Yau and Andre, 1997

4. Speiser, 1965

5. Iijima and Potemra, 1978 Dawn-Dusk Merging of Field-Aligned Currents Systems R2 R1 R1 R2

6. Ideal MHD Current: Anti-symmetric Ogino, 1986

7. Multi-Fluid Equations Ideal MHD Neglect all cyclotron terms No Parallel Electric Fields Accurate treat of system if its is in pressure balance No Ion Differentiation No Current Sheet Acceleration (aka Speiser motion)

8. Multi-Fluid Equations More Accurate Solution

9. For the Ions Not Zero

10. Polar (Thermal) Winds Fixed Ionospheric Density and Temperature; Zero Velocity Gravity , T, V determine by magnetospheric driving and ionospheric conditions Resistive Earth/Atmos. H+: 400 cm-3, 10 eV eq., 0.1 eV polar O +: 5% Inner Radius : 2.5 Re Grid Resolution: 0.25 Re

11. Southward IMF (-8 nT for 80 min) Northward IMF (8 nT for 60 min) Zero IMF

12. 12 T = 0410 T = 0313 T = 0337 18 06 00 12 T = 0420 T = 0430 T = 0250 18 06 00

15. Solar Wind Density cm-3 1 0.01 -50 Re 20 Re

16. Ionospheric H+ Density cm-3 1 0.01 -50 Re 20 Re

17. Relative Ionospheric O+ Density % 40 20 10 -50 Re 20 Re

18. Ionospheric O+ Temperature -50 Re 20 Re

19. Cross-Polar Cap Potential

20. Effective Plasma Resistivity (Cross-Polar Cap Potential/Total Ionospheric Current)

21. Effective Ohmic Dissipation (Cross-Polar Cap Potential*Total Ionospheric Current)

22. Modification of reconnection 20 Re -50 Re Side View

23. Modification of reconnection 20 Re -50 Re Top View

24. Midnight O+ Ionospheric Outflow Dawn Dusk 20 Re 50 Re Velocity (1000 km/s)

25. Midnight O+ Ionospheric Outflow 12 18 06 00

26. Full O+ Ionospheric Outflow 12 18 06 00

27. M/I Coupling for an Idealized Substorm • Larger response of heavy ionospheric ions to activity and increases the effective ionospheric conductivity • Midnight light ions and pre-midnight heavy ions have access to tail reconnection region • Acceleration leads to locally high concentrations of O+ AND asymmetric tail reconnection • Ion cyclotron affects lead to the generation of flux ropes • The asymmetries lead to distortion of the field-aligned current system

28. Apr 17, 2002 Storm

32. Solar Wind Density

33. Relative O+ Density

34. Ionospheric H+ Temperature

35. Equatorial Bz Positive Negative

36. Top View of Magnetic Field lines

37. Storm Activity • Northward pressure pulse leads to large entry of solar wind plasma • Eventually excluded by ionospheric plasma • Large IMF swings allow protons not oxygen to rapidly respond • Both increases and decreases in effective conductivity • Large IMF variations also allow both sunward and tailward motion of the near-Earth neutral line • Latter part of the even during sustained southward IMF should allow build up of O+

38. Ionospheric O+ Density cm-3 1 0.01

39. Solar Wind Temperature

40. Ionospheric H+ Temperature

41. Duskside O+ Ionospheric Outflow Dawn Dusk 16 Re 55 Re Velocity (1000 km/s)

42. Duskside O+ Ionospheric Outflow 12 18 06 00

43. Cusp O+ Ionospheric Outflow Dawn Dusk 16 Re 55 Re Velocity (1000 km/s)

44. Cusp O+ Ionospheric Outflow 12 18 06 00

45. Dawn O+ Ionospheric Outflow Dawn Dusk 16 Re 55 Re Velocity (1000 km/s)

46. Dawn O+ Ionospheric Outflow 12 18 06 00