Stable Auroral Arc (SAR)

About Stable Auroral Arc:

• It is a rare atmospheric phenomenon which was observed during a strong G3-class geomagnetic storm.
• Unlike auroras, which occur when charged particles from space hit the atmosphere causing it to glow, SAR arcs form differently.
• They are an indication of heat energy leaking into the upper atmosphere from Earth's ring current system, a donut-shaped circuit carrying millions of amps around our planet.
• During the recent geomagnetic storm, the ring current was energised by hours of intense geomagnetic activity, with energy dissipating into these SAR arcs.
• This global event was registered in many parts of the world.

How does Aurora form?

• It is formed when the sun is ejecting charged particles from its corona, creating solar wind. When that wind slams into Earth's ionosphere, the aurora is born.
• In the Northern Hemisphere, the phenomenon is called the northern lights (aurora borealis), while in the Southern Hemisphere, it's called the southern lights (aurora australis).
• The hemispheric asymmetry of the aurora is due in part to the sun's magnetic field interfering with Earth's magnetic field.