Self-consistent model of cosmic ray penetration into molecular clouds: Effect of energy losses

2025/10/03 by Chernyshov, D. O., Ivlev, A. V., Dogiel, V. A.
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE)

paper · doi:10.48550/arxiv.2510.03073

Abstract

The theory of cosmic-ray (CR) penetration into dense molecular clouds developed recently for relativistic particles by Chernyshov et al. (2024) is extended to non-relativistic CRs. Interstellar CRs streaming into the clouds are able to resonantly excite MHD waves in diffuse cloud envelopes. This leads to the self-modulation, such that streaming particles are scattered at the self-generated waves. In contrast to relativistic CRs, transport of lower-energy particles in the envelopes is generally heavily affected by ionization losses; furthermore, both CR protons and electrons contribute to wave excitation. We show that these effects have profound impact on the self-modulation, and can dramatically reduce CR spectra even for clouds with moderate column densities of a few times 10²¹ cm^-2.

Citations

• Re-evaluation of the cosmic-ray ionization rate in diffuse clouds
• Magnetic Fields in Molecular Clouds

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