Geomagnetic Storms

Context: Rare red auroras were seen in the skies over Oregon, United States after a G-1 class Geomagnetic storm hit Earth recently.

What are Geomagnetic Storms?

• Geomagnetic storms are disturbances in the Earth’s magnetic field caused by fluctuations in the solar wind, a stream of charged particles flowing from the sun.
• Mechanism of geomagnetic storms:
  • The solar wind is made up of charged particles, mainly electrons and protons that are constantly streaming out from the Sun’s outermost layer, called the corona.
  • When the solar wind encounters the Earth’s magnetic field, it creates a shock wave in the magnetosphere, the region around the Earth that is influenced by its magnetic field.
  • The shock wave can cause the magnetic field lines in the magnetosphere to be compressed or stretched, which can result in a sudden release of energy.
  • This energy release can cause the magnetic field to fluctuate rapidly, leading to a geomagnetic storm.

• Factors that determine the severity of a geomagnetic storm:
  • The severity of a geomagnetic storm depends on several factors, including the strength and speed of the solar wind, as well as the orientation of its magnetic field relative to the Earth’s magnetic field.
  • When the solar wind is strong and its magnetic field is aligned with the Earth’s magnetic field, it can cause more severe geomagnetic storms.
• Impacts of geomagnetic storms:

• Classification of Geomagnetic Storms: The National Oceanic and Atmospheric Administration (NOAA) classifies geomagnetic storms into five categories based on their intensity.
  • The Kp-Index (Planetary Index): The Kp index is the value assigned to geomagnetic storms in the NOAA classification.
    • The Kp index is a measure of the strength of geomagnetic disturbances over a 3-hour period, based on readings from a network of magnetic observatories around the world.
    • The Kp index ranges from 0 to 9, with higher values indicating more severe geomagnetic storms.

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