Marco Padovani, CSIC-IEEC, Barcelona
Jeudi 3 Novembre - 11 h 00
Salle Manuel Forestini - IPAG
Cosmic-rays constitute the main ionising and heating agent in dense, starless, molecular cloud cores. The main goal of this work is the calculation of the ionisation rate in a cloud resulting from the collisions between cosmic-ray particles (protons and electrons) and the matter constituting the cloud, mainly molecular hydrogen. We reexamine the physical quantities necessary to determine the cosmic-ray ionisation rate (especially the cosmic ray spectrum at E < GeV and the ionisation cross sections), and calculate the ionisation rate as a function of the column density of molecular hydrogen, through careful numerical integrations. Finally, we compute the attenuation of the cosmic-ray flux rate in a cloud core taking into account magnetic focusing, magnetic mirroring, and all relevant energy loss processes.
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