Aurora
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Transcript of Aurora
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Aurora
Stan SolomonHigh 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
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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+(B2u
+) N2+(B2u
+) N2+(X1g
+) + h (1N bands)
e* + N2 e* + N2(B3g) N2(B3g) N2(X1g+) + h (1P bands)
e* + N2 e* + N2(A3u+) N2 (A3u
+) N2(X1g+) + h (VK bands)
N2 (A3u+) + O(3P) N2(X1g
+) + O(1S)
O(1S) O(3P) + h (5577Å)
e* + O(3P) e* + O(1S) O(1S) O(3P) + h (5577Å) ~1s
e* + O(3P) e* + O(1D) O(1D) O(3P) + h (6300Å)
O2+ + e- O + O(1D) O(1D) O(3P) + h (6300Å) ~100s
O(1D) + N2 O(3P) + N2
e* + N2 e* + N(4S) + N(2D) N(2D) N(4S) + h (5200Å)
NO+ + e- O + N(2D) N(2D) N(4S) + h (5200Å) ~1e5s
N(2D) + O N(4S) + O
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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.)
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Photo Credits
Tom Eklund
Dave Fritts
NASA / Univ. Iowa
NASA / UC Berkeley
NASA STS
Stan Solomon