Front Cover -
Back Cover -
Synopsis -
Lecture 1 -
Lecture 2 -
Lecture 3 -
Lecture 4
TABLE OF CONTENTS
UJI LECTURES ON THE AURORA
Copyright 1997, 1998, by W. Calvert, all rights reserved.
Northern Lights -
Dedication -
Credits - Index -
Relevant Publications
- Next Lecture
Lecture 1. Previous Theories
1. Agenda
1. Filled-Loss-Cone Theory
2. Filled-Loss-Cone Theory of the Aurora
3. Loss Cone for Electron Precipitation into the Ionosphere
4. The Velocity-Space Distribution of Electrons Which Cause the Aurora
5. Electron Energy in the Ionosphere
6. Velocity Regimes which Contribute to the Aurora
2. Predicted Electron Precipitation for the Filled-Loss-Cone Theory
7. Predicted Precipitation for an Isotropic Initial Electron Velocity Distribution
8. Predicted Electron Precipitation Flux
9. Predicted Energy Flux
10. Relative Flux as a Function of the Altitude
at the Top of the Acceleration Region
11. Factors which Affect the Predicted Auroral Electron Precipitation Flux
12. Predicted Structure of the Aurora
3. Comparison with Inverted-V Electron Events
13. Inverted-V Electron Events
14. Average Latitudinal Width of an Inverted-V Electron Event
15. Comparison of Inverted-V Electron Events and Discrete Auroral Arcs
16. Spatial Resolution
4. New Observations which Disprove the Filled-Loss-Cone Theory
17. Oedipus-C
18. Trajectory of Oedipus-C
19. Aurora Detected at Poker Flats during the Oedipus-C Flight
20. Inverted-V Electrons Detected by Oedipus C
21. Discrete Arcs Detected by Oedipus-C
5. Source of the Electrons which Cause the Aurora
22. The Problem with Previous Theories
23. Previous Models for the Source of the Electrons which Cause the Aurora
24. New Model for the Source of the Electrons which Cause the Aurora
25. Summary of Lecture 1
- Next Lecture
Lecture 2. Convection and Scattering
26. Agenda for Lecture 2
6. Convection into the Loss Cone
27. Inward Convection driven by an Electric Field across the Magnetosphere
28. Convection Velocity as a Function of the Magnetic Latitude in the Auroral Zone
29. Time Delay for Inward Convection to Reach the Magnetic Latitudes were Substorm Onset Begins
30. Inward Convection of the Electron Acceleration Region
31. Inward Convection across Electric
Equipotentials
32. Electron Bounce Period
33. Convection into the Loss Cone
34. Predicted Electron Precipitation for Convection into the Loss Cone
35. Latitudinal Structure of the Aurora
7. Observations of Auroral Kilometric Radiation (AKR)
36. Auroral Kilometric Radiation
37. AKR during a Substorm
38. AKR from Discrete Arcs
39. Source Altitude
40. Wave Mode
41. Auroral Plasma Cavity
42. Discrete Spectra
43. Observed Bandwidth of the AKR Discrete Emissions
44. Discrete Emissions from Different Altitudes along the Same Field Line
45. Triggered AKR
8. Scattering into the Loss Cone
46. The Cyclotron Maser Instability
47. Scattering into the Loss Cone
48. Predicted Power of the Aurora
49. Electron Energy Loss inside Discrete Arcs
50. Summary of Lecture 2
- Next Lecture
Lecture 3. Substorm Onset and Discrete Auroral Arcs
51. Agenda for Lecture 3
9. Observations of the Aurora during a Substorm
52. The Aurora during an Auroral Substorm
53. The First Discrete Arc of Substorm Expansion
54. Thin Arcs detected by Akasofu in 1961
55. Measured Thickness of Discrete Auroral Arcs
56. Apparent Shape of Thin Discrete Arcs
57. Features which ought to be Accounted for by a Theory of the Aurora
10. Radio Lasing
58. Electronic Oscillators
59. Spectral Quenching
60. Laser Theory
61. Wave Field inside an Optical Laser
62. Frequency and Spectral Bandwidth
63. Radio Lasing inside a Local Density Depletion
64. AKR Discrete Emissions
65. Size, Power, and Beamwidth of an AKR Radio Laser
66. Diffraction Loss in a Radio Laser
67. Wave Field inside an AKR Radio Laser
68. Predicted Electron Precipitation by an AKR Radio Laser
11. Substorm Onset
69. What Causes an Auroral Substorm?
70. Origin of the Density Depletions in which Radio Lasing Occurs
71. Enhanced Scattering inside a Local Density Depletion
72. Time Required to Decrease the Density along an Auroral Field Line
73. Explanation for the Diffuse Aurora prior to Substorm Expansion
74. Explanation for Substorm Onset
75. Summary of Lecture 3
-First Lecture
Lecture 4. Substorm Expansion and Triggering
76. Agenda for Lecture 4
12. Triggering
77. Auroral Kilometric Radiation Triggered by a Type II Solar Radio Burst
78. Properties of Triggered AKR
79. Expected Time Delay for the Onset of Substorm Expansion
80. Advancing the Onset of Substorm Expansion
81. Explanation for the Triggering of Auroral Kilometric Radiation
13. Explanation for Substorm Expansion
82. The Domino Theory of Substorm Expansion
83. Observed Triggering of Discrete AKR by the AKR from an Adjacent Arc
84. Diffuse Electron Precipitation During Substorm Expansion
85. Why Substorm Expansion occurs in the Poleward Direction
86. Explanation for Substorm Expansion
14. Artificial Triggering
87. An Outlandish Prediction in 1981
88. Comparison of Substorm Onset and Triggered AKR
89. Two Practical Applications for Triggering the Aurora
90. Estimate of the Power that is Needed to Trigger the Aurora
91. The IMAGE Radio Plasma Imager
92. Measuring the Magnetosphere With RPI
93. RPI Specifications
94. A Unique Opportunity to Trigger the Aurora with RPI
15. Summary
95. Explanation for the Aurora which has Fascinated Mankind for Centuries
96. Features of the Aurora which are Accounted for by this Theory
97. Deduction Diagram (Part 1)
98. Deduction Diagram (Part 2)
99. Wakaru Club
Fifty years ago auroral research could be summarized as follows:
Some say that the Northern Lights
are the glare ...
of the Arctic ice and snow,
And some that it's electricity,
and nobody seems to know.
— Robert Service, in Ballad of the Northern Lights
This booklet is dedicated to Linda,
who suffered more than I did during its production,
and to my mother whom she cared for while I was
off having fun giving these lectures in Japan.
The cute little man who is triggering the aurora in Transparency 82 was provided courtesy of Corel Corporation Limited, 1600 Carling Avenue, Ottawa, Ontario, Canada, and the sound of the triggered aurora in this transparency is "gotcha-kata-kata-kata...", as suggested by Mrs. Abe of RASC. The scanning photometer observations in Transparency 19 were provided courtesy of Dr. H. G. James, Communications Research Centre, Ottawa, Ontario, Canada, and the Oedipus-C observations that were used to make Transparencies 20, 21, 49, and 84 were provided courtesy of Dr. D. A. Hardy, Phillips Laboratory, Hanscom Air Force Base, Bedford, Massachusetts. The DMSP data in Transparencies 13, 14, and 16 were provided courtesy of Dr. P. A. Newell of Applied Physics Laboratory, Laurel, Maryland. A description of these data is also available on the world wide web at http://sd-www .jhuapl .edu /Aurora /story3.sci.html. The Geotail data in Transparencies 36 and 45 were provided courtesy of Dr. H. Matsumoto of RASC. Other figures were also reproduced from the references indicated.
Dr. Y. Omura, Prof. K. Hashimoto, and Prof. H. Matsumoto, and the students and staff of RASC have assisted more than they realize by patiently listening to this theory, by discussing its merits, and by reviewing the introduction to the viewgraphs which follow. I am also quite pleased and honored to have been invited to spent the summer of 1997 at RASC.
Calvert, W., The stimulation of auroral kilometric radiation by type III solar radio bursts, Geophys. Res. Lett., 8, 1091-1094, 1981.
Calvert, W., A feedback model for the source of auroral kilometric radiation, J. Geophys. Res., 87, 8199-8214, 1982.
Calvert, W., Auroral precipitation caused by auroral kilometric radiation, J. Geophys. Res., 92, 8792-8794, 1987.
Calvert, W., An explanation for auroral structure and the triggering of auroral kilometric radiation, J. Geophys. Res., 100, 14,887-14,894, 1995.
Calvert, W., Do localized electric fields cause the structure of the aurora?, Eos Trans. AGU, 78, 309-310, 1997.
Calvert, W., Predicted electron precipitation for a filled loss cone at the top of the auroral electron acceleration region, Geophys. Res. Lett., 25, 13-16, 1998.
Calvert, W., The gotcha-kata-kata or "domino" theory of substorm expansion, Proceedings of the Fourth International Conference on Substorms, March 9-13, 1998.
Calvert, W., Electron precipitation caused by convection into the larger loss cone on lower-latitude field lines, Proceedings of the Fourth International Conference on Substorms, March 9-13, 1998.
Calvert, W., and D. A. Hardy, Local increases in auroral electron precipitation which were not accompanied by a corresponding increase in the electric potential of the auroral electron accelera tion region, Geophys. Res. Lett., 24, 2933-2936, 1997.
Transparency 34: The wrong graph was shown for the electron precipitation that is caused by convection into the loss cone.
Transparency 54: A better version is shown of the photograph of thin discrete arcs by Akasofu [1961].
W. Calvert
219 Friendship Street
Iowa City, Iowa, 52245, USA
email: calvert@fyiowa.infi.net
Telephone: 319-337-6368
FAX: 319-354-2170