Eruptive versus confined X-class flares in solar cycles 23 and 24

A systematic analysis on the properties of all GOES X-class solar flares (SFs) in solar cycles 23 and 24 (1996-2019) is performed. The occurrence rates and parameters of the eruptive and confined SFs are presented. The aspect of eruptivity versus confinement is investigated with respect to the co-occurrence of coronal mass ejections (CMEs), radio emissions, energetic protons and geomagnetic storms. The absence of interplanetary type III radio bursts, in addition to the lack of CMEs, is found to be a very good proxy for confinement, in contrast to the sunspot type of the parent active region, as both eruptive and confined SFs are predominantly of beta-gamma-delta magnetic type. The remaining parameters, protons and geomagnetic storms, imply observing from a specific location in the heliophere and thus are biased for Earth-reaching phenomena. Finally, the relationships between the two types of SFs and the considered here solar activity phenomena are discussed in view of previous studies.