Ilya Usoskin
University of Oulu, Finland
Extreme solar eruptive events: Rare but dangerous
Solar energetic eruptive processes, such as flares and coronal mass ejections, are relatively well-studied during the past decades of direct observations. Although their maximum strength/energy is not constrained by direct data because of a too short period of observations, we know that extreme events do occur rarely on the Sun over the last millennia. This is known from both the multi-millennial data of extreme solar activity using cosmogenic-proxy data, and also from a several-year survey of thousands of sun-like stars, thanks to high-precision stellar photometry. From these datasets, we can estimate the occurrence probability of extreme solar events and even reconstruct their energy spectra and assess the dramatic terrestrial and societal impacts. The consistency of different datasets on the average flux of solar energetic particles at the Earth’s orbit can be assessed.