ATMO/ECE 489/589 Spring 2005 - Outline of Possible Topics

1. Introduction

1.1 Historical overview

1.2 Review of classical electricity and magnetism

• Coulomb’s law and Maxwell’s equations
• Boundary value problems
• Electrical units

2. Fair Weather Electricity

2.1 Sources of atmospheric ions

• Natural radioactivity
• Radon & Thoron - “Radon Hazard”
• Cosmic rays
• Point discharge

2.2 Chemistry of the primary ions

2.3 Small ion mobilities

2.4 Ion-ion recombination

2.5 Characteristics of the atmospheric aerosol

2.6 Ion-aerosol attachment

2.7 Electrical structure of the troposphere

• Ion balance equations
• Conductivity profiles
• Fair weather electric fields
• Air-earth currents
• Global electric “circuit”
• Solar-terrestrial interactions

8. Applications

3. Cloud Electricity

3.1 Microstructure of clouds

3.2 Ion-droplet diffusion

3.3 Electrical structure of non-thundery clouds

3.4 Development and evolution of thunderstorms

3.5 Thunderstorm electric fields

• Measurements
• Screening layers
• Effects on cloud microphysics
• Charge structure of thunderclouds

3.6 The thunderstorm as a current source

• Spatial characteristics
• Temporal development

3.7 Thundercloud electrification

• Basic charging requirements

- Ion capture and induction mechanisms

• Electrical properties of water and ice
• Thermoelectric and contact mechanisms
• Ice-graupel collisions – laboratory data
• Observations in clouds
• Large scale charge separation

3.8 Lightning initiation

• Gas breakdown phenomena

­ Behavior of water drops in electric fields

• Models of lightning initiation

2. Lightning

4.1 Basic lightning phenomenology

• Area densities & strike probabilities
• Cloud-to-Ground flashes
• Preliminary breakdown
• Stepped-leader
• Return strokes
• Dart leader
• J- and K-processes
• Intracloud discharges

4.2 Triggered Lightning

4.3 Characteristics of lightning currents

4.4 Physical characteristics of lightning channels

• Dimensions
• Thermodynamic properties
• Energy balance

4.5 Thunder

4.6 Chemistry of lightning processes

4.7 Electric and magnetic fields produced by lightning

• Time-domain antenna theory
• Radio frequency emissions

4.8 Propagation, sferics, and atmospheric radio noise

4.9 Methods of detecting and locating lightning

• Gated, wideband sensors (MDF & TOA)
• RF Techniques
• Satellite lightning sensors

4.10 Electrical transients at high altitudes, “Sprites” and “Elves ”

4.11 Global lightning activity

2. Lightning Protection and Lightning Safety

5.1 Mechanisms of lightning damage

5.2 Principles of lightning protection

• Grounding, bonding and shielding
• Transient protectors
• Shielding topology

5.3 Methods of protection against lightning

• Buildings
• Hazardous structures
• Telecommunications and data systems
• Electric-power transmission/distribution systems
• Aircraft and avionics systems

4. Lightning test equipment, methods and standards

5. Lightning safety recommendations

6.0 Possible Additional Topics

• Ions and health
• Stratospheric electricity
• The ionosphere
• The magnetosphere
• Auroral phenomena
• Whistlers
• Electricity in planetary atmospheres
• Ball lightning