Stars form due to the gravitational collapse of dense molecular clouds. The process of star formation is still not completely understood, but it is believed that a crucial parameter that regulates star formation is the ionization level in the dense cores of molecular clouds. This is because the ionization level is determining the coupling between the gas and the magneticl field, which is in turn affecting the dynamics of the collapse through magnetic pressure support. Due to the very high density of molecular clouds, ionizing UV radiation is absorbed and cannot penetrate to the clouds' cores, and thus the only ionizing agents there are cosmic rays. 

Cosmic rays are energetic particles that fill the whole Galaxy. Their penetration into molecular clouds depends (again!) on the magnetic field strenght and turbulent structure. This process is non-linear, because cosmic ray themselves can generate the magnetic turbulence they are scattered off. 

The aim of this work is to study from a theoretical point of view the penetration of ionizing cosmic rays into clouds. 

It is intriguing to note that also the origin of cosmic rays is, to date, still unknown. They are believed to be accelerated at supernova remnant shocks, but a final proof of this hypothesis is still missing. Thus, the research proposed here will be part of an attempt to solve one of the longest standing issue in «traditional» Astronomy - How do stars form? - together with the key question of cosmic ray physics – Where do cosmic rays come from?