About South Atlantic Anomaly (SAA):
- It is a unique location on Earth where the magnetic field is weaker than normal.
- It is southeast of South America and southwest of Africa. In this area, the planet's magnetic field dips down.
- It was first identified in the 19th century.
- Why does it occur?
- Earth’s magnetic field acts like a protective shield around the planet, repelling and trapping charged particles from the Sun.
- SAA exists because the Earth’s inner Van Allen radiation belt comes closest to the planet’s surface, causing an increased flux of energetic particles.
- This leads to the penetration of solar energetic particles deep into Earth’s atmosphere, posing severe problems for airplanes and ships’ positioning systems as well as spacecraft electronic systems.
What are the Van Allen Radiation Belts?
- The Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind.
- The particles are captured by and held around a planet by that planet’s magnetic field.
- It surrounds Earth, containing a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.
- The outer belt is made up of billions of high-energy particles that originate from the Sun and become trapped in Earth’s magnetic field, an area known as the magnetosphere.
- The inner belt results from interactions of cosmic rays with Earth’s atmosphere.
- The Van Allen belts are most intense over the Equator and are effectively absent above the poles.
