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Stable Auroral Arc (SAR)

10th November, 2023 Geography

Stable Auroral Arc (SAR)

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  • The Indian Astronomical Observatory (IAO) in Ladakh recently acquired breathtaking photographs of a rare red aurora known as a Stable Auroral Arc.


  • It is a rare atmospheric event that occurred during a strong G3-class geomagnetic storm.
  • SAR arcs form differently than auroras, which arise when charged particles from space collide with the atmosphere, making it light.
  • They are a result of thermal energy escaping into the upper atmosphere from Earth's ring current system, which is a donut-shaped circuit that transports millions of amps around our planet.
  • The recent geomagnetic storm energized the ring current, with energy dispersing into these SAR arcs.
  • This global occurrence was recorded in various places of the world.


How does Aurora form?

  • It forms when the sun ejects charged particles from its corona, resulting in solar wind. When that wind collides with the Earth's ionosphere, the aurora is born.
  • The phenomenon is known as the northern lights (aurora borealis) in the Northern Hemisphere and the southern lights (aurora australis) in the Southern Hemisphere.
  • The aurora's hemispheric asymmetry is due in part to the sun's magnetic field interfering with Earth's magnetic field.


The Stable Auroral Arc (SAR) has been a subject of growing interest in the field of space science. Examine the characteristics, formation mechanisms, and scientific significance of the Stable Auroral Arc.