A plea for first-principles radiative models in solar energetic events

Radio emissions have a wide exploitation potential both in the remote diagnosis of their plasma sources, often impossible to explore in-situ, but also in the context of space weather for developing realistic forecasting models for the effects of energetic solar events, such as coronal plasma ejections (CMEs) on modern technologies on ground and in space. Here we discuss the importance of first-principle radiative models, not only for these applications but especially for developing realistic models for type-II and type-III radio emissions whose plasma sources are likely to be explored in situ by different satellites and spacecraft. At this early stage, first-principle radiative models combine a fundamental kinetic theory for describing wave instabilities in plasma sources, with numerical simulations of their saturation by nonlinear processes that generate free-propagating radio waves. We also discuss a series of further additions, in particular with nonlinear theories of the various wave-wave couplings responsible for the generation of radio emissions.