Scientists from the Indian Institute of Astrophysics (IIA) have reported observations of a flareless coronal mass ejection (CME) from the solar atmosphere with the Visible Emission Line Coronagraph (VELC) instrument onboard Aditya-L1 mission.

Key Observations

• A CME erupted in July, 2024, without any associated flare.
• VELC captured the onset of the CME, offering valuable clues about:
  • Magnetic instabilities on the Sun.
  • Differentiation between flares and CMEs.
• Unique Advantage: VELC’s design allows observation of CMEs near the solar limb and their onset time, facilitating better investigation of their association with flares.

What are Flares and CMEs?

• Flares: Explosive events releasing energy as electromagnetic radiation from heated plasma.
  • Cause: Magnetic reconnection (rearrangement of magnetic field lines).
• Coronal Mass Ejections (CMEs): Massive eruptions of plasma and magnetic fields from the Sun.
  • Scale: Weigh about trillion kilograms.
  • Speed: Can travel up to 3,000 km/s through interplanetary space.
  • Ambiguity: The relationship between flares and CMEs is not fully understood.

Scientific Importance

• Understanding Solar Activity: Differentiating the mechanisms behind flares and CMEs.
  • Studying magnetic instabilities that trigger these events.
• Solar Cycle 25: The Sun is approaching the maximum phase of its current solar cycle (Cycle 25), leading to more frequent CMEs.
  • Continuous monitoring by VELC will provide critical data for the global scientific community.
• Technological Impact: Improved understanding of CMEs can enhance space weather forecasting, crucial for protecting satellites and communication systems.

About Visible Emission Line Coronagraph (VELC)

• It is an internally occulted solar coronagraph to carry out simultaneous imaging, spectroscopic and spectro-polarimetric observations of the solar corona from close to the solar limb. 
• Primary science goals for the payload are: 
• • to understand heating of the solar corona; 
  • observations of the origin and development of coronal mass ejections near the Sun; 
  • observations of coronal magnetic field topology and measurement of their strength over active regions; 
  • coronal loop oscillations.

Scientific and Technological Significance

• Advancement in Solar Physics: Provides critical data to address fundamental questions about the Sun’s corona, magnetic fields, and explosive events like CMEs.
• Space Weather Forecasting: Enhances our ability to predict space weather events, which can affect satellites, communication systems, and power grids on Earth.
• Global Contribution: Positions India as a key player in solar research and space exploration.
• Interdisciplinary Applications: Findings from VELC can contribute to fields like plasma physics, magnetohydrodynamics (MHD), and astrophysics.

About Aditya L1 Mission

• Launch Date: The Indian Space Research Organisation (ISRO) launched the Aditya-L1 mission on September 2, 2023, from the Satish Dhawan Space Centre in Sriharikota.
• Mission Goal: Aditya-L1 is India’s first dedicated scientific mission to study the Sun.
• Current Orbit: Aditya-L1 was placed in a halo orbit around the Earth-Sun Lagrange point (L1) on January 6, 2024.
• Mission Lifespan: Aditya-L1 is designed to operate for five years, continuously observing and gathering data on solar phenomena.

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