Aditya-L1 Mission Provides New Clues to Sun's Extremely Hot Corona

India's Aditya-L1 solar mission has yielded significant findings that may solve the long-standing mystery of why the Sun's outer atmosphere, the corona, is millions of degrees hotter than its visible surface. A new study, published in The Astrophysical Journal Letters, suggests that magnetic-field reconnection is the dominant mechanism responsible for heating the corona.

The research, led by Prof. R. Ramesh of the Indian Institute of Astrophysics, analyzed data from Aditya-L1's Visible Emission Line Coronagraph (VELC) during a powerful coronal mass ejection (CME) on August 5, 2024. The study indicates that magnetic reconnection provides approximately 93% of the energy required to sustain the corona's high temperatures, with turbulent surface waves contributing only about 7%.

Scientists have long grappled with the coronal heating problem, as the Sun's visible surface is around 5,500°C, while the corona can reach millions of degrees. The study observed that following the August 2024 CME, the Sun's magnetic structures reconfigured within about 10 hours, offering strong evidence that magnetic reconnection rapidly replenishes energy lost during such eruptions.

These insights from Aditya-L1 are expected to serve as a crucial benchmark for future research into solar energy generation and transport. A deeper understanding of these processes could also lead to improved prediction and mitigation of solar flares and CMEs, which have the potential to disrupt satellites, communications, and power grids on Earth.