Contents

• Dedication
• Abstract
• Acknowledgements
• List of Figures
• 1. Introduction
  • 1.1 Units and fundamental equations
  • 1.2 Thunderstorms and cloud-to-ground lightning
  • 1.3 Electrical environment of the nighttime upper atmosphere
  • 1.4 Contributions
• 2. Lightning Direct Coupling
  • 2.1 Electrical discharges in weakly ionized gases
    • 2.1.1 Definitions
    • 2.1.2 Breakdown scaling laws
    • 2.1.3 Inelastic collisions
    • 2.1.4 Streamer breakdown and other energetic processes
    • 2.1.5 VLF absorption and reflection
  • 2.2 Heating of the lower ionosphere by the lightning electromagnetic pulse: elves
    • 2.2.1 Theoretical studies of elves
    • 2.2.2 Experimental optical studies of elves
  • 2.3 Lightning quasielectrostatic fields and mesospheric discharges: sprites
    • History and nomenclature
    • The diffuse region of sprites
    • Corona streamers in sprites
    • ELF determination of current moments
    • Spectral studies
  • 2.4 Electromagnetic model
    • 2.4.1 Heating
    • 2.4.2 Ionization
    • 2.4.3 Optical emissions
  • 2.5 Model Results
    • 2.5.1 Ionization changes in the lower ionosphere
    • 2.5.2 Early/fast VLF perturbations
    • 2.5.3 Multiple events
• 3. Instrumentation and Atmospheric Propagation
  • 3.1 ELF and VLF sferic recordings
  • 3.2 Atmospheric optical propagation
    • 3.2.1 Cloud and Rayleigh-scattering: temporal considerations
    • 3.2.2 Scattering and absorption as a function of wavelength
    • 3.2.3 Atmospheric refraction
  • 3.3 Broadband photometry
    • 3.3.1 Surface Brightness
    • 3.3.2 Calibration
    • 3.3.3 Band brightness at the source
  • 3.4 The Fly's Eye
    • 3.4.1 Pointing Calibration
    • 3.4.2 Intensity Calibration
  • 3.5 Intensified CCD video recordings
    • 3.5.1 GPS time stamping
    • 3.5.2 High speed video
    • 3.5.3 Star-field matching
• 4. Photometry of Elves
  • 4.1 Identification of lightning, elves, and sprites
    • 4.1.1 Modeled optical signatures
    • 4.1.2 Observed photometric signatures
    • 4.1.3 Discrimination of elves from Rayleigh-scattered lightning
    • 4.1.4 Video signatures of elves
  • 4.2 Correlation with positive and negative lightning strokes
  • 4.3 Determination of flash location using high-resolution timing
  • 4.4 Distribution of elves throughout large storm systems
  • 4.5 Two-color photometry
• 5. Combined Photometry and Imagery of Sprites
  • 5.1 Sprite halos
    • 5.1.1 Modeled optical signatures
    • 5.1.2 High speed video observations
    • 5.1.3 Sprite halos in normal-rate video
    • 5.1.4 Sprites and elves in photometry
    • 5.1.5 Dependence on the ambient electron density
    • 5.1.6 Independence of sprite halos and streamer breakdown
  • 5.2 Sprite polarity
    • 5.2.1 Observations
    • 5.2.2 Discussion
  • 5.3 Exponential optical decay and steady electric fields
    • 5.3.1 Timescales in sprite photometry
    • 5.3.2 Observations of exponential optical decay
    • 5.3.3 Steady electric currents
    • 5.3.4 Steady electric fields and streamer velocities
• 6. Conclusions and Suggestions
  • 6.1 Conclusions
    • Indirect measurement of ionization
    • Remote sensing of the electric field
    • Discrimination of 1 ms flashes
    • Verification of theoretical models
    • Ubiquity of sprites and elves
  • 6.2 Further Research
    • Three-dimensional modeling of VLF propagation past diffuse sprite regions: Early/fast events
    • Telescopic high-speed video
    • Multi-anode photometric arrays
• Bibliography
• Index
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