Download
slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Multi-Fluid/Particle Treatment of Magnetospheric-Ionospheric Coupling During Substorms and Storms PowerPoint Presentation
Download Presentation
Multi-Fluid/Particle Treatment of Magnetospheric-Ionospheric Coupling During Substorms and Storms

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

114 Vues Download Presentation
Télécharger la présentation

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

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  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

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

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

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

  16. Ionospheric O+ Temperature -50 Re 20 Re

  17. Cross-Polar Cap Potential

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

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

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

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

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

  23. Midnight O+ Ionospheric Outflow 12 18 06 00

  24. Full O+ Ionospheric Outflow 12 18 06 00

  25. 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

  26. Apr 17, 2002 Storm

  27. Solar Wind Density

  28. Relative O+ Density

  29. Ionospheric H+ Temperature

  30. Equatorial Bz Positive Negative

  31. Top View of Magnetic Field lines

  32. 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+

  33. Ionospheric O+ Density cm-3 1 0.01

  34. Solar Wind Temperature

  35. Ionospheric H+ Temperature

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

  37. Duskside O+ Ionospheric Outflow 12 18 06 00

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

  39. Cusp O+ Ionospheric Outflow 12 18 06 00

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

  41. Dawn O+ Ionospheric Outflow 12 18 06 00