Radio tools for the forecasting of coronal mass ejections and solar energetic particles

Radio observations of heliospheric plasmas, and particularly radio observations of the Sun, are of threefold interest for space weather: (1) Solar radio bursts may on occasion be a space weather hazard of their own, when strong bursty emission perturbs communication frequencies used, e.g., for GNSS navigation or air traffic control radar. (2) Because of their ability to trace eruptive activity in the corona, spectrographic and imaging observations at radio frequencies are a tool in post-event analyses to identify the context where hazardous events arise. (3) Since radio emission is an early messenger of eruptive processes in the solar corona, it can serve as a forecast tool. The latter aspect will be the focus of the present contribution.