Context: Recently, Scientists say that earth’s magnetic field is gradually weakening which is resulting in technical disturbances in some satellites orbiting our planet.
About Magnetic field of Earth

• The magnetic field is vital for life on earth as it protects us from the harmful cosmic radiation and charged particles emitted from the sun.
• The field is mostly generated by the ocean of super-hot liquid iron that makes up Earth’s outer core, around 3,000 km below the earth crust.
• It creates electric currents that generate and change our electromagnetic field.
• This field varies in strength and direction and over the last 200 years, it has lost around 9% of its strength.

South Atlantic Anomaly (SAA)

• Earth’s magnetic field has been weakening across a wide stretch of area for reasons unknown. Scientists have found the magnetic field from Africa to South America to be gradually weakening.
• However, a rapid shrink has been observed in the South Atlantic Anomaly (SAA), a stretch between Africa and South America. It 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. 
• According to the data given by the ESA, the magnetic field has lost nearly nine per cent of its strength on a global average in the last 200 years. This year, the “minimum field strength” in the South Atlantic Anomaly has seen a drop of around 24,000 nanoteslas to 22,000 from its strength in 1970.

About A Van Allen radiation belt

• It 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.
• Earth has two such belts and sometimes others may be temporarily created.

Pole reversal/Geomagnetic reversal

• One most speculated reason behind this is that there is a chance that the time for Earth's pole reversal is coming near. 
• Pole reversal is when the north and south magnetic poles flip. While this flip will not occur immediately or suddenly, and will happen over centuries, there would be multiple north and south magnetic poles during this period, all around the planet. 
• This is definitely not the first time that pole reversal will be happening on the Earth. This event has occurred few times in the history of our planet, as per the scientists and we are long overdue by the average rate at which these reversals take place (roughly every 250,000 years).  

Impact

• The impact of such a geomagnetic reversal could be significant, given the role of Earth’s magnetic field in protecting the planet from solar winds and harmful cosmic radiation.
• Also, as the telecommunication and satellite systems also rely on the magnetic fields to operate, the computers and mobile phones could experience difficulties.
• Another impact of the reversal will be on birds, turtles and other creatures that use the magnetic field to navigate.
• The North on a compass will point to Antarctica rather than Canada.
• The satellites and other spacecraft flying through the area are more likely to experience technical malfunctions, so charged particles can penetrate the altitudes of low-Earth orbit satellites.