Key facts
- The Sun's corona is millions of degrees hotter than its surface, a long-standing scientific mystery.
- Findings from India's Aditya-L1 solar mission suggest magnetic field reconnections are the primary energy source for the corona.
- These reconnections supply 93% of the energy needed to maintain the corona's high temperature.
- Solar surface waves contribute only 7% of the energy.
- The study analyzed a significant CME event on August 5, 2024, using Aditya-L1's Velc instrument.
Astrophysicists in India have presented new findings from the Aditya-L1 mission that shed light on the enduring mystery of why the Sun's outer atmosphere, the corona, is millions of degrees hotter than its surface. Published in the Astrophysical Journal Letters, the study quantifies the energy contributions from two key phenomena: the bubbling motions on the Sun's surface that generate waves, and the snapping and reconnecting of magnetic field lines in the Sun's atmosphere.
According to the research led by Prof R Ramesh of the Indian Institute of Astrophysics, the corona's temperature, which can reach up to 40 million degrees Celsius, is primarily maintained by the magnetic field lines. These lines, often twisted and looping, rupture during events like coronal mass ejections (CMEs), releasing vast amounts of energy. The study found that these reconnections replenish approximately 93% of the energy lost by the corona.
In contrast, the energy transported by waves generated from the Sun's surface boiling motions contributes only about 7% to the corona's energy requirement. The researchers arrived at these calculations by studying a highly energetic CME that occurred on August 5, 2024. Data from Aditya-L1's Visible Emission Line Coronagraph (Velc) showed that the magnetic field lines returned to their original configuration and reconfigured the corona's energy within 10 hours after the event.
This research provides crucial data for understanding the energy generation mechanisms in the Sun's atmosphere and addresses fundamental questions in physics that have long puzzled scientists.