Stable Auroral Arc (SAR)

Disclaimer: Copyright infringement not intended.

Context

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

About

• 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.