Statistical Links between Solar Cosmic Rays, Type-II Radio Emission, and Coronal Mass Ejections

Type-II radio emission often accompanies events in solar cosmic rays and is an indicator of the propagation of a shock wave in the solar corona. Conversely, the shock wave associated with coronal mass ejections plays an important role in the acceleration of solar protons. Both of these phenomena can occur unaccompanied by solar cosmic rays, while not all solar cosmic ray events are accompanied by type-II radio emission. The statistical relationships between these phenomena are considered based on the catalogs of solar proton events for the 23rd and 24th solar-activity cycles. It is shown that the events of solar cosmic rays accompanied by type-II radio emissions are among the most powerful in terms of both particle characteristics and source characteristics.