Sun-Earth Connection:

1. Sun-Earth Connection: Energy and Momentum Transfer from the Solar Wind to the Magnetosphere and the Ionosphere Gang Lu HAO/NCAR

2. Solar and Magnetospheric Energy Budget Solar irradiance: 1017 W (with 0.1% variability) Solar wind kinetic power: 1013~1014 W Magnetospheric power: 1011~1013 W • auroral precipitation: 109 ~ 1011 W • Joule heating rate: 1010 ~ 1012 W • ring current injection: 1010 ~ 1012 W • plasma sheet heating: ~ 1011 W • Plasmoid ejections: 1010~ 1011 W • coupling efficiency: 1~10 % • energy input to the magnetosphere: 1023~1024 ergs • energy released by a typical CME: 1031 ergs

3. Chapman-Ferraro Magnetosphere stream Cusp Earth C-F Current Layer stream Cusp Top View Side View [Kennel, 1995]

4. Earth’s Magnetosphere [Hill and Dessler, 1991]

5. 12 6 18 0 Axford-Hines “Closed Model”

6. Possible Sources of Viscosity Collision

7. Possible Source of Viscosity Collision Diffusive Entry

8. Possible Source of Viscosity Collision Diffusive Entry Kelvin-Helmholtz Instability

9. Dungey “Open Model” x

10. Southward IMF [Lyons and Williams, 1985]

11. Northward IMF [Potemra et al., 1984] [Heppener & Maynard, 1987]

12. Magnetospheric Current Systems [Kivelson and Russell,1995]

13. Ionospheric Currents (neglecting neutral winds) Horizontal Current: JH JH JP JP Field-aligned Current:

14. - + - + - + - + - +

15. - R1 + R1 - + R1 R1 - + - + - +

16. - R1 + R1 - - + + R1 - R1 + - e- + p+ - + - + - +

17. - R1 + R1 - - + + R1 - R1 + - e- + p+ - + - + - +

18. - + - - + + - + - e- + p+ - + - + - +

19. - + - - + + - + - e- + p+ - + - + - +

20. Energy Flow Poynting’s Theorem: Electric energy is much smaller than magnetic energy since: For quasi-steady-state conditions, the Poynting’s theorem reduces to: magnetic energy mechanical or thermal energy mechanical energy magnetic energy

27. Neutral Wind Dynamo Effects Ionospheric energy dissipation/generation: Mechanical power Joule heating where is the electric field in the neutral wind frame Joule heating with neutral wind: Field-aligned current (FAC) with neutral wind: In general, neutral winds tend to reduce total Joule heating and FAC

28. Neutral Wind Dynamo Effects At high-latitude regions, neutral wind has the “flywheel” effect when there is a rapid reduction in plasma convection, For example, due to the south-to-north turning of the IMF Neutral wind is the major dynamo forcing at mid- and low-latitude regions where they are mostly shielded from the high-latitude electric field due to the magnetospheric forcing

29. Height-Integrated Power Convection Heating Wind Cooling Total Power Mechanical Power

30. Height-Integrated Field-aligned Current Ion Drift Driven Neutral Wind Driven

31. (courtesy of Mewaldt and Zurbuchen)

32. Magnetic Cloud Magnetic Cloud 08:24 05:00 11:02

33. SEP Magnetic Cloud Magnetic Cloud 08:24 05:00 11:02

35. Impact of SEP on Upper Atmosphere

37. 7.2x1025 3.6x1024 3.2x1024 2.5x1024 1.1x1024 Total Energy (x1024 ergs)

42. Height-Integrated Power Convection Heating Wind Cooling Total Power Mechanical Power

43. Total Power Mechanical Power

44. Sun-Earth Connection: Energy and Momentum Transfer from the Solar Wind to the Magnetosphere and Ionosphere Gang Lu HAO Seminar, 30 April 2003