Geomagnetic Storm – UPSC Prelims

What is a Geomagnetic Storm?
  • 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.
  • Solar Storms occur during the release of magnetic energy associated with sunspots and can last for a few minutes or hours.
  • The magnetosphere shields our home planet from harmful 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.
  • These storms result from variations in the solar wind that produce major changes in the currents, plasmas, and fields in Earth’s magnetosphere.
  • 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, with its embedded magnetic field, arrives at Earth.
  • CMEs are large ejections of plasma and magnetic fields that originate from the Sun’s corona (outermost layer).
Geomagnetic Storm’s impact on Earth:
  • Can Impact Space Weather:
    • It can impact space weather in near-Earth space and the upper atmosphere.
  • Can Hit Operations of Space-Dependent Services:
    • Solar storms can hit operations of space-dependent services like Global Positioning Systems (GPS), radio, and satellite communications. Aircraft flights, power grids, and space exploration programmes are vulnerable.
  • Can Potentially Create Disturbances in the Magnetosphere:
    • Coronal Mass Ejections (CMEs) with ejectiles loaded with matter travelling at millions of miles an hour, can potentially create disturbances in the magnetosphere, the protective shield surrounding the Earth.
    • Astronauts on spacewalks face health risks from possible exposure to solar radiation outside the Earth’s protective atmosphere.
How are Solar Storms Predicted?
  • Solar physicists and other scientists use computer models to predict solar storms and solar activities in general.
  • Current models are capable of predicting a storm’s time of arrival and its speed.
  • But the storm’s structure or orientation still cannot be predicted.
  • Certain orientations of the magnetic field can produce a more intense response from the magnetosphere, and trigger more intense magnetic storms.
  • With the increasing global dependence on satellites for almost every activity, there is a need for better space weather forecasts and more effective ways to protect satellites.