Solar flares and eruptions are among the most powerful events in the solar system, and can even affect terrestrial activities. They involve localized regions on the solar surface and corona, and we can observe and resolve them in the high energy bands with telescopes on-board satellites. Flares are even more powerful in active stars and in protostars, but because of the distance we are unable to resolve them, as well as many other details of those stellar systems.

Star-forming regions are especially interesting for us because they show how our own Sun and planets were born. We know from observations that protostars are surrounded by an accretion disk, from which planets form, and it is debated that mass flows presumably along magnetic channels. Possible questions are then: can we use the Sun itself as a template, and in particular transient solar events? Can we learn something from solar flares and eruptions about magnetic connections and mass flows from accretion disks to protostars? The answer goes through the fundamental mediation of physical models, and the results can be surprising.