What do we learn from Ground Level Enhancements?

Athanasios Papaioannou, National Observatory of Athens, IAASARS, Penteli, Greece

Ground-level enhancements (GLEs) comprise the high-energy end of solar energetic particle (SEP) events and constitute a special class in which ions are accelerated to relativistic energies, causing a significant sudden increase of cosmic rays at ground-based detectors, mainly at neutron monitors (NMs). GLEs require acceleration processes capable of producing particles with sufficient intensity to allow their secondary products to reach the terrestrial ground and be detected. Moreover, due to their fast propagation, relativistic protons in GLEs are particularly useful for the identification of SEP sources at the Sun (i.e. flare, coronal mass ejections) - nonetheless, the debate about the exact nature of GLE mechanisms is still ongoing. GLEs are further critical for the establishment of Space Weather services and the accurate determination of their imposed radiation risk. In this tutorial, an overview of GLEs with respect to their historical identification, measurements from the worldwide neutron monitor network our modeling and forecasting efforts will be provided. A tutorial that will demonstrate how the Neutron Monitor Database (NMDB) can be utilized for GLE analysis will be conducted.