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The study of the interaction of cosmic rays with the interstellar matter is a multi-disciplinary investigation that involves the analysis of several physical and chemical processes: ionisation of atomic and molecular hydrogen, energy loss by elastic and inelastic collisions, energy deposition by primary and secondary electrons, gamma-ray production by pion decay, the production of light elements by spallation reactions, and much more. Cosmic-ray ionisation activates the rich chemistry of dense molecular clouds and determines the degree of coupling of the gas with the local magnetic field, which in turn controls the collapse timescale and the star-formation efficiency of a molecular cloud. In recent years a wealth of observations from the ground and from space has provided information and constraints that still need to be incorporated in a consistent global theoretical framework. My goal is to use the results of chemical models and state-of-the-art numerical simulations supplemented by dedicated observations to provide a unifying interpretation of the data with a model of cosmic-ray propagation specifically developed to make predictions that can be tested against the observations. Finally, I will talk about my most recent study: a mechanism able to accelerate local thermal particles in protostars that can be used to explain the high ionisation rate as well as the synchrotron emission observed towards protostellar sources.

The accurate and timely prediction of solar eruptions is important for many space weather prediction tools and the Solar Orbiter mission. The aim of this study is to propose a new technique for the automated prediction of magnetic flux rope ejections in data driven NLFFF simulations hours in advance. We use a data-driven NLFFF model to describe the evolution of the 3D magnetic field of 8 active regions: 5 that produced an eruption and 3 where no eruption was observed. From the 3D magnetic field configuration, we determine a possible proxy for the loss of equilibrium of the magnetic flux rope based on the Lorentz force. Such proxy is significantly higher for the simulations of the eruptive active regions. For some cases, using a subset of the observed magnetograms, we ran a series of predictive simulations to test whether the time evolution of the proxy project forward in time can be used to predict the eruptions. We find that the identified proxy is useful in anticipating the magnetic flux rope ejection and that a meaningful prediction can be made up to 10 hours in advance. Although a number of issues need to be addressed for a fully operational application, this study presents an interesting solution for the prediction of CME onsets and future studies will address how to generalise the model such that it can be used.