Coffee Lectures 2026

Ludwig Klein
Ground level enhancement GLE #77 on 11 November 2025: a data summary

A very strong solar energetic particle event took place on 11-Nov-2025. It was registered by the worldwide network of neutron monitors as a ground-level enhancement (GLE) #77. The peak and integral intensities of GLE #77 reached about 125 (165) % and 600 (800) %hr, respectively, for standard (bare) neutron monitors. It had a complicated, multi-component anisotropic structure caused by the complexity of the solar coronal and heliospheric conditions. In this talk, based on a collective work published in Advances in Space Research (https://ui.adsabs.harvard.edu/abs/2026AdSpR..77.9764M/abstract), verified datasets related to this event are discussed along with some preliminary analyses. The solar and heliospheric conditions are overviewed, including the analysis of solar EUV, X-ray and radio-emission with an attempt to infer the location of the primary particle acceleration. Measurements of solar energetic particles in space, near the first Sun-Earth Lagrange point (L1) onboard the SOHO spacecraft, and in geostationary orbit onboard the GOES-19 spacecraft, are presented, revealing a long-duration, hard-spectrum intense solar particle event.