Tag Archives: geoeffective

229. Source-Region Magnetic Evolution and Precursors of the X9.0 Flare in Solar Cycle 25

Contributed by Yijun Hou. Posted on June 8, 2026

Persistent magnetic flux emergence with perpendicular separation directions in AR 13842 rapidly formed a collisional shearing PIL, with frequent flux cancellations there, leading to repeated magnetic flux rope formations and multiple large flares. The pre-flare decreases in the sheared PIL’ s area and free-energy density may serve as a promising precursor for major eruptive flares.