Solar Orbiter Unveils 'Magnetic Avalanche' Triggering Massive Solar Flares

The European Space Agency's (ESA) Solar Orbiter mission has delivered definitive observational proof of a phenomenon known as a "magnetic avalanche," which acts as the catalyst for powerful solar flares. This landmark discovery was made possible by data collected on September 30, 2024, during the spacecraft's perihelion—the point in its elliptical orbit where it is closest to the Sun. The findings, which were officially published on January 21, 2026, in the esteemed journal "Astronomy & Astrophysics," provide a much-needed empirical foundation for theoretical models that previously relied on statistical analysis rather than direct visual evidence.

To capture this event, the Solar Orbiter operated at a distance of roughly 45 million kilometers from the solar surface, a proximity that allowed for an extraordinary level of visual detail. The flare in question, classified as an M7.7 event, was observed from the limb of the solar disk, providing an ideal perspective for the mission's instruments. A key factor in the success of this observation was the high-frequency imaging capability, which recorded data every two seconds. This allowed scientists to witness how minor reconfigurations within the solar magnetic fields can cascade and intensify, much like a physical avalanche, until they culminate in a violent explosion. Approximately 40 minutes before the peak intensity, a dark "filament" of twisted magnetic fields was identified, linked to a cross-shaped structure that steadily brightened as the event progressed.

The climax of the solar discharge occurred at approximately 23:47 UTC, at which point charged particles were accelerated to staggering speeds between 40% and 50% of the speed of light. This translates to a velocity range of 431 to 540 million kilometers per hour. Following the peak, the mission recorded a "rain of plasma blobs" that continued to fall back into the solar corona long after the primary flare had subsided. A significant takeaway for the research team was that not all the energy released by the flare is projected into space; a portion is instead absorbed by the surrounding plasma through these falling blobs. This observation is particularly relevant given the current phase of high solar activity noted in early 2026.

This scientific breakthrough was the result of a coordinated effort involving several key institutions and researchers. Among the lead contributors were Lakshmi Pradeep Chitta from the Max Planck Institute for Solar System Research (MPS), Sami K. Solanki, who serves as the director of MPS and the principal investigator for the PHI instrument, and Miho Janvier, the ESA Solar Orbiter project scientist. The comprehensive data set was generated by the simultaneous operation of four specialized instruments: EUI, PHI, SPICE, and STIX. The EUI instrument was responsible for monitoring plasma at temperatures near 1 million degrees, while the STIX instrument focused on the significantly hotter regions where high-speed particles deposited their energy.

The implications of this discovery extend far beyond academic curiosity, as they have direct applications for monitoring and predicting space weather. Because intense solar flares have the potential to damage satellite infrastructure and disrupt terrestrial power grids, understanding the "magnetic avalanche" mechanism is vital for improving our early warning systems. By identifying the precursors to these events, scientists hope to safeguard critical technology on Earth and in orbit. Furthermore, the research team is now investigating whether this avalanche mechanism is a universal characteristic of flares on other stars, which could reshape our understanding of stellar dynamics throughout the universe.