⚡ Solar Wind and Aurora Formation
The Aurora Borealis occurs when charged particles from the solar wind interact with Earth's magnetosphere and atmosphere, creating spectacular light displays.
The Solar Wind Process
- Solar Wind: Stream of charged particles flowing from Sun at 400-800 km/s
- Interplanetary Magnetic Field: Magnetic field carried by solar wind
- Bz Component: North-south orientation critical for Aurora
- Magnetic Reconnection: When solar and Earth's fields connect
🧲 Why Bz Direction Matters
Southward Bz (-) can reconnect with Earth's northward magnetic field, opening pathways for particles to enter our magnetosphere and create Aurora.
🌍 Earth's Magnetic Shield
Earth's magnetosphere acts as a protective shield, but when solar wind conditions are right, particles can penetrate and create Aurora displays.
🎨 Aurora Colors and Altitude
Color Formation by Gas Type
- Green (557.7 nm): Oxygen atoms at 100-300 km altitude
- Red (630.0 nm): Oxygen atoms above 300 km
- Blue/Purple: Nitrogen molecules at lower altitudes
- Pink: Mix of red oxygen and blue nitrogen