India’s first solar mission Aditya-L1 generates Doppler velocity images of the solar corona

ISRO’s Aditya-L1 solar mission enters Halo orbit. File | Photo credit: ANI

Scientists have created Doppler velocity images of activity in the solar corona using data obtained by the Visible Emission Line Coronagraph (VELC) aboard India’s first solar mission, Aditya-L1.

The Aditya-L1 satellite generates Doppler velocity images of the solar corona, and these images are expected to provide previously unavailable information on the Sun-Earth propagation of coronal mass ejections (CMEs).

What the scientists say

Scientists from the Indian Institute of Astrophysics (IIA), who created the Doppler velocity images, said it is well known that solar activity leads to the ejection of hot plasma.

They said that the massive and energetic plasma plume ejected during powerful eruptions such as a CME can move either in the direction of Earth or in any other direction away from the Sun.

The researchers said that because CMEs can disrupt near-Earth space, it is important to infer their direction of propagation from the Sun when they erupt.

“It is commonly taught in high schools that the Doppler effect in sound helps to understand whether a train is approaching or moving away from a station platform. A person standing on the platform would hear a continuous increase in the pitch of the sound waves due to the whistle or horn of the train as the train approaches the station. As the train moves away, the pitch decreases continuously,” the researchers said.

Using a similar concept of the Doppler effect in light waves, they have now generated Doppler velocity images.

What doppler velocity shows

“Positive and negative Doppler velocities indicate that the solar plasma is moving away from and toward the observer,” they said.

Detailed VELC data processing software was developed by Dr. V. Muthupriyal, Principal Project Scientist with the VELC Operations Team at the IIA, and her team. Technical details related to the data processing were recently published in the Astrophysical Journal following international peer review.

According to Prof. According to R. Ramesh, IIA Senior Professor and Principal Investigator of the VELC project, Doppler images of the velocity of the solar corona are unique.

He said that only VELC currently has the ability to generate such images due to its unique ability to observe spectroscopically in the visible wavelength range from the Lagrangian L1 position in the Sun-Earth system.

He added that the associated processed images will be disseminated to the scientific community, in addition to the data that is already publicly available.

Published – 20 Oct 2026 10:48 IST