Astrophysicists from India’s Aditya-L1 solar observation mission have published findings that shed light on a long-standing scientific puzzle: why the Sun’s corona, its outermost atmospheric layer, maintains temperatures around 2 million degrees Celsius—or sometimes as high as 40 million degrees—when the Sun’s visible surface reaches only about 5,500 degrees Celsius. The research, led by Prof R Ramesh of the Indian Institute of Astrophysics, was published in the Astrophysical Journal Letters.
The corona regularly experiences extreme weather events such as solar flares and coronal mass ejections, or CMEs, during which the Sun releases enormous amounts of energy into space. During normal solar activity, the Sun produces two to three CMEs daily, a number that can increase to ten or more per day during peak activity cycles that occur every 11 years. These eruptions pose challenges for Earth’s infrastructure, potentially disrupting power grids and communication satellites through geomagnetic storms, while also creating auroras in the upper atmosphere.
The scientific challenge centers on understanding how the corona replenishes its energy after such massive losses. Scientists have long identified two potential mechanisms: waves generated by churning motions on the Sun’s surface that carry energy outward, and the snapping and reconnecting of tangled magnetic field lines in the corona. Through analysis of a significant CME recorded on 5 August 2024 using Aditya-L1’s Visible Emission Line Coronagraph instrument, researchers quantified each mechanism’s contribution to the corona’s energy budget.
The study reveals that magnetic field reconfiguration supplies approximately 93 percent of the energy needed to maintain the corona’s extreme temperatures, while surface wave motion contributes only about 7 percent. Within ten hours of the August 2024 CME, the disrupted magnetic field lines reconnected and the corona’s energy was restored. Prof Ramesh indicates these findings provide crucial data for future investigations into atmospheric energy generation mechanisms and may help resolve fundamental physics questions about stellar atmospheres.
Article Attribution | Read More at Article Source
Article summary produced by Claude AI