This Lund Observatory seminar will be held by Chiara Paleari from the department of Geology. 

Title: The search for extreme solar particle storms in polar ice cores 

Abstract: Solar energetic particles are emitted in association with solar flares and coronal mass ejections and contribute to the production of cosmogenic radionuclides stored in environmental archives, such as ice cores and tree rings. Our knowledge regarding solar particle storms is mostly limited to the advent of neutron monitors in the 1950s, and satellites in the 1970s. Modern events, however, were not powerful enough to leave any significant imprint in the radionuclide records from ice cores and tree rings. In the last decade, five extreme solar particle storms were detected in radionuclide records from ice cores and tree rings over the last 10,000 years. Using ice core radionuclide data it is possible to reconstruct the spectral hardness and fluence spectra of the events, which are estimated to be about 100 times larger than modern events, as well as their relationship with solar activity levels.