Thunderstorm electrification relies on specific processes occurring within the cloud. The efficient separation of electrical charge requires the interaction of different types of particles.
Cloud Composition for Electrification
Efficient charge separation and electrification in thunderstorms primarily occur in clouds containing a mixture of:
- Ice crystals
- Supercooled liquid droplets (water droplets below 0°C but still liquid)
- Graupel (soft hail or snow pellets formed by accretion of supercooled water onto ice crystals)
- Hailstones (larger ice particles)
Mechanism of Charge Separation
The interaction and collision between these particles, especially graupel and ice crystals in the presence of supercooled water, are key to the electrification process. These collisions lead to charge transfer between the colliding particles, resulting in the separation of positive and negative charges within the cloud volume. Clouds composed solely of one type of particle (like only ice or only liquid droplets) are less efficient at producing the strong electrical fields characteristic of thunderstorms.
Important Questions from Atmospheric Electricity
The sequence of events in a cloud to ground electrical discharge is
- In the global electrical circuit, the negative charge on the Earth is maintained predominantly by
- Electrical discharge suddenly heats the conducting air channel in the Earth's atmosphere, which expands and generates shock waves. These waves spread as
- Fair weather electrical field near the Earth's surface is typically about
- The upper part of a thunderstorm cloud is normally — charged, and the middle and lower parts are — charged
