演講資訊

摘要：

Dense molecular clouds play important role in cosmic rays studies. Due to their high mass, low temperature and very high density as compared to the interstellar plasma, they are often referred to as "space calorimeters". Multi-wavelengths observations of these objects can help us determine spectra of cosmic rays in the distant parts of the Galaxy. This information may be crucial for the understanding on how cosmic rays are accelerated and how are they being confined in the Galaxy. On the other hand, cosmic ray studies also important for understanding star formation. Indeed, cosmic rays can penetrate deep into the dense clouds, far beyond the ultra-violet photons, and therefore they can ionize medium in the darkest regions of the clouds. Therefore, they can trigger and enhance star formation in the molecular clouds cores.

To carefully study these two problems, one should know how charged particles penetrate the dense gas. Since cosmic rays experience intense energy losses inside, the non-zero flux of particles directed towards the molecular cloud will be formed. And as a result of streaming instability zone of high turbulence will be formed in the clouds envelope, preventing particles from propagating into the cloud. Therefore, the interaction of particles with clouds is non-trivial and is described by a system of non-linear equations. I will show that this effect can be described by a simple analytic solution, allowing easily to estimate the flux of particles into the cloud and the spectra they form inside.