On September 30, 2024, the Sun unleashed a powerful explosion, causing magnetic field lines to break and reconnect in a criss-cross pattern. A Sun-observing probe was there to watch it unfold, gathering unprecedented data that\u2019s helping scientists better understand the mechanism behind solar flares.<\/p>\n
Using the European Space Agency\u2019s Solar Orbiter spacecraft, a team of scientists discovered that solar flares are triggered by initially weak disturbances that grow more violent, similar to avalanches on snowy mountains. The process creates a sky of raining plasma blobs that continue to fall even after the solar flare has subsided, according to a new study<\/a> published in Astronomy & Astrophysics.<\/p>\n Magnetic avalanche <\/p>\n Solar flares are giant explosions on the Sun<\/a>, flinging energy, light, and particles into space. They take place when energy that\u2019s stored in twisted magnetic field lines is suddenly released. The most powerful solar flares can disrupt technologies on Earth, triggering geomagnetic storms<\/a> capable of causing radio blackouts.<\/p>\n Scientists have observed solar flares for years, but they still lack a detailed understanding of how this colossal amount of energy is released so rapidly from the Sun. Using the high-resolution data from Solar Orbiter, scientists now have a better picture of the process that leads to the violent eruption.<\/p>\n Solar Orbiter zoomed in on a region of the Sun with a dark arch-like \u2018filament\u2019 of twisted magnetic fields and plasma, linked to a cross-shaped structure of brightening magnetic field lines. Scientists directed the spacecraft\u2019s Extreme Ultraviolet Imager (EUI) toward the region roughly 40 minutes before peak flare activity.<\/p>\n By zooming in, observations revealed new magnetic field strands appearing in every image frame\u2014equivalent to every two seconds or less. Each strand was magnetically contained and twisted like a rope. The region became progressively less stable, just like in an avalanche.<\/p>\n The twisted magnetic field strands began to break and reconnect, rapidly triggering a cascade of further instability in the region. As the strands broke, they triggered progressively stronger reconnection events and outflows of energy, which appeared as increasing brightness in the images.<\/p>\n Then, a sudden brightening was followed by the dark filament disconnecting from one side, launching into space while violently unrolling at high speed. Scientists first recorded the unwinding at 155 miles per second (250 kilometers per second), rising to 248 miles per second (400 km\/s) at the site of disconnection. Bright sparks of reconnection appeared all along the filament in stunning high resolution as the flare erupted.<\/p>\n