Geomagnetic storms and magnetosphere

Context: Researchers have traced a very significant increase in special continuous oscillations with pearl-type structures called Geomagnetic Pc1 pearl oscillations on the surface of the Earth in the recovery phase of geomagnetic storms. This study is significant for investigating of precipitation particles during geomagnetic storms and can help us understand the radiation hazard to satellites and astronauts.

What are geomagnetic storms?

• A geomagnetic storm is a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth. 
• These storms result from variations in the solar wind that produces major changes in the currents, plasmas, and fields in Earth’s magnetosphere. 
• The solar wind conditions that are effective for creating geomagnetic storms:
  • Sustained (for several to many hours) periods of high-speed solar wind. 
  • Southward directed solar wind magnetic field (opposite the direction of Earth’s field) at the dayside of the magnetosphere. This condition is effective for transferring energy from the solar wind into Earth’s magnetosphere.
  • High-speed solar wind stream (HSS).
• The largest storms that result from these conditions are associated with solar coronal mass ejections (CMEs) where a billion tons or so of plasma from the sun arrives at Earth. 
• Storms also result in intense currents in the magnetosphere, changes in the radiation belts, and changes in the ionosphere, including heating the ionosphere and upper atmosphere region called the thermosphere. 

How Solar flares are formed?

Impacts of such storms:

• Increase in the density in the upper atmosphere, causing extra drag on satellites in low-earth orbit. 
• Horizontal variations in the in the ionospheric density that can modify the path of radio signals and create errors in the positioning information provided by GPS. 
• Storms create beautiful aurora. 
• They also can disrupt navigation systems such as the Global Navigation Satellite System (GNSS).
•  They can create harmful geomagnetic induced currents (GICs) in the power grid and pipelines.

What is Magnetosphere?

• It is the region around a planet dominated by the planet’s magnetic field. Other planets in our solar system have magnetospheres, but Earth has the strongest one of all the rocky planets.
• Earth’s magnetosphere is a vast, comet-shaped bubble, which shields our home planet from solar and cosmic particle radiation, as well as erosion of the atmosphere by the solar wind – the constant flow of charged particles streaming off the sun. 
• It is generated by the convective motion of charged, molten iron, far below the surface in Earth’s outer core. 
• Constant bombardment by the solar wind compresses the sun-facing side of our magnetic field. The sun-facing side, or dayside, extends a distance of about six to 10 times the radius of the Earth. The side of the magnetosphere facing away from the sun – the nightside – stretches out into an immense magnetotail, which fluctuates in length and can measure hundreds of Earth radii, far past the moon’s orbit at 60 Earth radii.

Difference between Ionosphere and Magnetosphere?

• The ionosphere is a region within the upper mesosphere and thermosphere where solar radiation and particles in the “solar wind” strip electrons from atoms in the atmosphere and create an electrically charged zone of ions. It is used to communicate long distances by radio. Radio waves bounce off the ionosphere in much the same way that light is reflected by a mirror. The ionosphere changes its position from day to night, rising in the night and lowering in the day. This is why radio signals from far off places can be detected at night, while only close by transmissions are detectable during the day.
• The magnetosphere is Contained within the Earth’s thermosphere and is the region where the Earth’s magnetic field interacts with the charged particles coming from the Sun in the solar wind. These particles become trapped in the magnetic field of the Earth and circulate around the Earth following the Earth’s magnetic field. Large bombardments of these charged particles cause the auroras in the ionosphere as they follow the Earth’s magnetic field through the upper atmosphere towards the magnetic poles.

What are 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.