1 Aurora Stan Solomon High Altitude Observatory National Center for Atmospheric Research Summer Colloquium on Space Weather NCAR Advanced Studies Program 7 June 2005

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8 Is the Aurora Borealis similar to the Aurora Australis?

9 Reconnection in the Magnetotail

10 Coupled Magnetosphere-Ionosphere-Thermosphere Model

11 Energetic Particles from the Magnetosphere

12 Motion of Charged Particles Along a Magnetic Field Line

13 Transport of Auroral Electrons in the Upper Atmosphere

14 Penetration Depth of Auroral Electrons Depends on Energy

15 Thermosphere and Ionosphere Composition

16 Auroral Collisional Processes Electron Impact Ionization

17 Ion Recombination Processes

18 Simplified Schematic of Ion-Neutral Chemistry

19 Examples of Auroral Emission Processes e* + N 2  2e* + N 2 + (B 2  u + )N 2 + (B 2  u + )  N 2 + (X 1  g + ) + h (1N bands) e* + N 2  e* + N 2 (B 3  g )N 2 (B 3  g )  N 2 (X 1  g + ) + h (1P bands) e* + N 2  e* + N 2 (A 3  u + )N 2 (A 3  u + )  N 2 (X 1  g + ) + h (VK bands) N 2 (A 3  u + ) + O( 3 P)  N 2 (X 1  g + ) + O( 1 S) O( 1 S)  O( 3 P) + h (5577Å) e* + O( 3 P)  e* + O( 1 S)O( 1 S)  O( 3 P) + h (5577Å)  ~1s e* + O( 3 P)  e* + O( 1 D)O( 1 D)  O( 3 P) + h (6300Å) O e -  O + O( 1 D) O( 1 D)  O( 3 P) + h (6300Å)  ~100s O( 1 D) + N 2  O( 3 P) + N 2 e* + N 2  e* + N( 4 S) + N( 2 D)N( 2 D)  N( 4 S) + h (5200Å) NO + + e -  O + N( 2 D)N( 2 D)  N( 4 S) + h (5200Å)  ~1e5s N( 2 D) + O  N( 4 S) + O

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31 Question for Discussion Is this a good analogy? The aurora has been compared to a cathode-ray tube (e.g., TV set, computer monitor, etc.)

32 Photo Credits Tom Eklund Dave Fritts NASA / Univ. Iowa NASA / UC Berkeley NASA STS Stan Solomon