Characteristics of active regions associated to large solar energetic proton events

The relationship between properties of active regions (ARs) and solar energetic particles (SEP events, protons with energy ⩾10 MeV) is examined. For this purpose we study 84 SEP events recorded during the SOHO era (1996-2014). We compare properties of these SEP events with associated ARs, flares and CMEs. The ARs are characterized by McIntosh classification. Statistical analysis demonstrates that SEP events are more likely to be associated to the ARs having complex magnetic structures and the most energetic SEPs are ejected only from the associated ARs having a large and asymmetric penumbra. This tendency is used to estimate intensities of potential SEP events. For this purpose we express a probability of occurrence of an SEP event from a given AR which is correlated with fluxes of associated SEPs. We find that SEP events associated with ARs from eastern longitudes have to be more complex to produce SEP events at Earth. On the other hand, SEP particles originating from mid-longitudes (30°