Polar Rain Aurora

• Context (WION): For the first time, a rare aurora named polar rain aurora or Christmas Day aurora was witnessed in the Arctic in 2022.

Aurora

• Aurora is a luminous glow that occurs when the charged particles from the Sun collide with gases in Earth’s upper atmosphere.
• Auroras are powered by electrons from the solar wind (a stream of charged particles that flow from the sun), trapped in Earth’s magnetic field extension called the magnetotail.
• When space weather becomes extreme, such as when a coronal mass ejection (a large ejection of plasma and magnetic field from the sun) is released, the magnetotail can be pinched off.
• The electrons trapped there flow down Earth’s magnetic field lines to the poles.
• As they do so, they collide with molecules in Earth’s atmosphere, prompting them to glow in auroral colours (blue for nitrogen and green or red for oxygen, depending on altitude).
• Normally, the aurora displays, moves and pulsates with clearly discernible shapes in the sky.

• For details on Aurora, visit > Solar Storms and Northern Lights and Aurora Lights

How is Polar Rain Aurora different from Normal Aurora?

• Polar rain aurora was a faint, featureless glow that spanned 4,000 km in extent. It had no structure, no pulsing or varying brightness.
• It occurred when the solar wind gusts had greatly diminished, creating a calm region around Earth.