1. Atmospheric Electricity

2. Dalibard’s Experiment

3. The Earth’s Electric Field

4. The “Carnegie” Curve: measurements of the Earth’s Electric Field Thunderstorm Frequency

5. Charging Mechanisms Induction –Result is a polarized hydrometeor Ion particle charging Particle-particle charging E + + + + + - - - - -

7. Charging by induction Initially neutral Introduce a charge, creating an electric field + - - - - - + + + + + E

8. Charging by induction Contact charging - + E

9. Selective Ion Capture - - - - - - - - - - + + + + + + + + + + - + E

10. Gravity plays a role in differential charge separation Negative charge transfer to larger particles, which then fall to lower levels in the cloud.

11. The Earth’s Electric Field

12. Storm Electrification Is NOT well understood There is more than one parameter –Buoyancy –Hydrometeor type –Conductivity Even within the same storm Role of charge separation

13. Corona or Point Discharge The presence of some sort of conductive point Disruption of the Electric Field Electron Avalanche (non-ohmic)

14. Corona (point discharge)

15. Lightning Types Frequency of occurrence

16. The Electrification of thunderstorms is related to thermodynamics

17. Different slopes for different storms

18. Why the slopes may differ

19. Flash rate is greatest when storm intensity is greatest

20. Cloud Physics and electrification

21. Hail and ground strokes

23. Field Mill