VELC on board Aditya-L1 reveals asymmetric expansion of solar eruption that could impact space weather

Key Highlights:

• Aditya-L1, India's first space-based solar observatory, has provided new insights into solar eruptions.
• Its primary payload, Visible Emission Line Coronagraph (VELC), revealed that Coronal Mass Ejections (CMEs) expand asymmetrically, not uniformly.
• This finding, published in Astrophysical Journal Letters, was based on combined data from VELC and NASA's SDO spacecraft.
• The asymmetric expansion of CMEs has significant implications for understanding and predicting Space Weather disturbances affecting Earth.

Detailed Insights:

• Aditya-L1 was launched in September 2023 and is operational at the Sun-Earth L1 point, offering continuous solar observations.
• The VELC payload, designed by Indian Institute of Astrophysics (IIA) with ISRO support, observes the solar corona using spectroscopy.
• The study utilized VELC's unique capability to measure Doppler shift in the 530.3 nm green emission line from hot coronal plasma.
• A 3-D geometric-kinematic model was developed to confirm that an inclined axis and asymmetric lateral expansion best reproduce the observed spectral patterns.
• Understanding this non-uniform expansion is crucial as it affects a CME's speed and arrival time at Earth, impacting satellites and communication networks.

Scientific/Technical Concepts Involved:

• Aditya-L1: India's first dedicated space mission to study the Sun, positioned at the Sun-Earth L1 point.
• Visible Emission Line Coronagraph (VELC): The primary instrument on Aditya-L1 that observes the solar corona by blocking the Sun's disk.
• Coronal Mass Ejection (CME): Large expulsions of plasma and magnetic field from the Sun's solar corona into space.
• Space Weather: Conditions in space, driven by solar activity, that can affect Earth's technological systems and human health.
• Doppler shift: The change in wavelength of light due to the relative motion of the source and observer, used to determine plasma velocity.