Aurora

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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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Is the Aurora Borealis similar to the Aurora
Australis?
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Reconnection in the Magnetotail
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Coupled Magnetosphere-Ionosphere-Thermosphere
Model
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Energetic Particles from the Magnetosphere
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Motion of Charged Particles Along a Magnetic
Field Line
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Transport of Auroral Electrons in the Upper
Atmosphere
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Penetration Depth of Auroral Electrons Depends on
Energy
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Thermosphere and Ionosphere Composition
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Auroral Collisional Processes
Electron Impact Ionization
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Ion Recombination Processes
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Simplified Schematic of Ion-Neutral Chemistry
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Examples of Auroral Emission Processes
e N2 ? 2e N2(B2Su) N2(B2Su) ?
N2(X1Sg) hn (1N bands) e N2 ? e
N2(B3Pg) N2(B3Pg) ? N2(X1Sg) hn (1P
bands) e N2 ? e N2(A3Su) N2 (A3Su) ?
N2(X1Sg) hn (VK bands) N2 (A3Su) O(3P)
? N2(X1Sg) O(1S) O(1S) ? O(3P)
hn (5577Å) e O(3P) ? e O(1S) O(1S) ?
O(3P) hn (5577Å) t1s e O(3P) ? e
O(1D) O(1D) ? O(3P) hn (6300Å) O2 e- ? O
O(1D) O(1D) ? O(3P) hn (6300Å)
t100s O(1D) N2 ? O(3P) N2 e N2 ?
e N(4S) N(2D) N(2D) ? N(4S)
hn (5200Å) NO e- ? O N(2D) N(2D) ? N(4S)
hn (5200Å) t1e5s N(2D) O ? N(4S) O
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Question for Discussion
The aurora has been compared to a cathode-ray
tube (e.g., TV set, computer monitor, etc.)
Is this a good analogy?
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Photo Credits
Tom Eklund Dave Fritts NASA / Univ. Iowa NASA /
UC Berkeley NASA STS Stan Solomon