WHAT IS SOUTH ATLANTIC ANOMALY

WHAT IS SOUTH ATLANTIC ANOMALY : SAA


The SAA is referred to the behaviour of Earth’s Geo-Magnetic field in an area between Africa and South America.
The SAA is an area where the Earth’s inner Van Allen radiation belt comes closest to the Earth’s surface, dipping down to an altitude of 200 kilometres.
This leads to an increased flux of energetic particles in this region and exposes orbiting satellites to higher-than-usual levels of radiation.
The effect is caused by the non-concentricity of the Earth and its magnetic dipole.
The SAA is the near-Earth region where the Earth’s magnetic field is weakest relative to an idealized Earth-centered dipole field.

Weakening of the magnetic field


Over the last 200 years, the magnetic field has lost around 9% of its strength on a global average.
A large and rapid shrink has been observed in the SAA region over the past 50 years just as the area itself has grown and moved westward.
The weakening of the magnetic field is also causing technical difficulties for the satellites and spacecraft orbiting the planet.
The study conducted between 1970 and 2020, said that the magnetic field 
weakened considerably in a large region stretching from Africa to South America, known as the ‘SAA’.
This area has grown and moved westward at a rate of around 20 km per year.



Its impact

The magnetic shield has an important role to play in keeping unwanted radiation away as well as helping determine the location of magnetic poles.
Even though unlike global warming or any weather change, this anomaly doesn’t directly impact human lives, it could actually bring on a change in the way we access technology.
The reversal and apparent shift, which could keep extending could actually impact satellite and telecommunication system, which means that some of the internet and mobile phone functioning which depend on satellite signals can possibly get disrupted.
It could also affect the mapping and navigation systems in smartphones.
The weakening of earth’s magnetic field could also impact migratory movement.
Birds, animals- all those who migrate with the change in season depend on the earth’s mapping to move about can find it a little difficult.
This is only a possibility, but we don’t know the extent of the damage till now.



About the Van Allen Radiation Belt


A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet’s magnetic field.
The belts are located in the inner region of Earth’s magnetosphere. The belts trap energetic electrons and protons.
Earth has two such belts and sometimes others may be temporarily created.
Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays.
By trapping the solar wind, the magnetic field deflects those energetic particles and protects the atmosphere from destruction.

Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in the Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of the Earth's magnetic field at its surface ranges from 25 to 65 microteslas. As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11 degrees with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of the Earth. The North geomagnetic pole, which was in 2015 located on Ellesmere Island, Nunavut, Canada, in the northern hemisphere, is actually the south pole of the Earth's magnetic field, and conversely.

EXTRA INFO: 

In electromagnetism, there are two kinds of dipoles:

An electric dipole deals with the separation of the positive and negative charges found in any electromagnetic system. A simple example of this system is a pair of electric charges of equal magnitude but opposite sign separated by some typically small distance.
A magnetic dipole is the closed circulation of an electric current system. A simple example is a single loop of wire with constant current through it. A bar magnet is an example of a magnet with a permanent magnetic dipole moment.




The area of the SAA is confined by the intensity of Earth's magnetic field at less than 32,000 nanotesla at sea level,[2] which corresponds to the dipolar magnetic field at ionospheric altitudes.[3] However, the field itself varies in intensity as a gradient



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