STABLE AURORAL ARC (Syllabus: GS Paper 1 – Geography)

News-CRUX-10     10th November 2023        
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Context: Recently, the Indian Astronomical Observatory (IAO) in Ladakh captured stunning images of a rare red-colored aurora known as a Stable Auroral Arc.

Stable Auroral Arc

  • About: It is a rare atmospheric phenomenon that was observed during a strong G3-class geomagnetic storm.
  • Unique Formation: Unlike auroras, which result from charged particles colliding with the atmosphere, SAR arcs form through a distinct process.
  • Heat Energy Indicating Earth's Ring Current: SAR arcs are a manifestation of heat energy escaping into the upper atmosphere from Earth's ring current system, a circular electrical circuit that carries millions of amperes around the planet.
  • Ring Current During Recent Storm: The recent geomagnetic storm intensified the ring current due to prolonged geomagnetic activity, causing energy to dissipate into these SAR arcs.
  • Global Observation: This exceptional event was documented in various regions across the world.

How does Aurora form?

  • Formation of Aurora: Aurora is created when the sun ejects charged particles from its corona, generating solar wind.
  • This solar wind interacts with Earth's ionosphere, giving birth to the aurora.
  • Northern Hemisphere: it is known as the northern lights or aurora borealis.
  • Southern Hemisphere: it is referred to as the southern lights or aurora australis.
  • Hemispheric Differences: The auroral asymmetry between hemispheres is partially attributed to the interference of the sun's magnetic field with Earth's magnetic field.
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