News: ISRO’s Aditya-L1 used its VELC instrument to generate Doppler velocity images of the solar corona → Helps determine solar plasma motion and improve assessment of Earth-directed CMEs.

Aditya-L1 Mission

• Launched by: ISRO → India’s first dedicated space-based solar observatory.
• Location: Sun–Earth L1 point, about 1.5 million km from Earth.
• Objective: Study the Sun’s atmosphere + solar activity + space weather.

VELC Instrument

• Full form: Visible Emission Line Coronagraph.
• Function: Observes the Sun’s faint corona by blocking its bright disc.
• Significance: Uses spectroscopic observations to generate Doppler velocity images.

Coronal Mass Ejections (CMEs)

• Large eruptions of plasma + magnetic fields from the Sun’s corona.
• Earth-directed CMEs → Can cause geomagnetic storms and affect satellites, communication, navigation + power grids.

Doppler Effect

• Blueshift → Source moves towards the observer.
• Redshift → Source moves away from the observer.
• Wavelength shifts help estimate plasma velocity along the line of sight.