Data from India’s highest space observatory in Ladakh helped track 2023’s most intense solar storm

Vijay Mohan

Chandigarh, March 1

Data generated by India’s highest deep space observatory located in Ladakh has helped astronomers to track the solar source of the most intense geomagnetic storm to hit Earth last year.

In late April 2023, a severe geomagnetic storm in the Earth’s magnetosphere led to a vivid display of the aurora in lower latitudes extending to places like Ladakh. The auroral light was captured by all sky cameras located at the Indian Astronomical Observatory at Hanle in Ladakh.

Astronomers found that the rotation of the filament structure when it was near the Sun was the leading cause behind this solar storm which resulted in a strong effect on the Earth, according to information shared by the Ministry of Science and Technology on Friday.

The Sun often ejects ionized gas, also known as plasma, and magnetic fields in the form of coronal mass ejections (CMEs) into inter-planetary space. When these CMEs encounter planets such as Earth, they interact with the planetary magnetic fields resulting in major magnetic storms.

Accelerated particles and geomagnetic storms can adversely affect human technology on Earth and in space. Thus, understanding and predicting CMEs has both scientific and practical importance.

A large-scale CME eruption originated from the ‘Active Region – 13283’ located near the solar disk center at midnight on April 21, 2023, resulting in the most intense geomagnetic storm of “Solar Cycle – 25’.

The CME was launched at a speed of about 1,500 kms per second and encountered the near-Earth environment on April 23 at 12:30 PM. Consequently, a severe geomagnetic storm commenced an hour later on Earth.

“Surprisingly, since the CME was launched from a weak magnetic field region on the Sun, such intense geomagnetic storms are unexpected. This is because the energization process is expected to be slower and the formation of twisted magnetic flux is also unlikely,” Dr P. Vemareddy, the author of the study undertaken by the Indian Institute of Astrophysics, explained in a statement issued by the Ministry.

Further, CME is associated with a pre-existing magnetized plasma filament in the source active region on the Sun. The magnetic fields evolve with the changing sign of its helicity a few hours before the eruption, which could be the prime destabilizing factor of the magnetic field equilibrium in the solar atmosphere.

This study indicates the importance of having a complete picture of CMEs, including their magnetic structure and the mechanisms involved in their origin from the solar source regions, their evolution, and their propagation from the Sun to the Earth, according to the ministry.

Researchers are also looking forward to using the observations of the Sun provided by India’s recently launched space observatory, Aditya – L1, which provides both remote as well as in situ observations, enabling experts to understand the CME launch on the Sun as well as its arrival at the near-Earth space. “In particular, imaging observations close to the Sun are crucial to determine the orientation and speed of the CME,” Dr Vemareddy said.