Exclusion of cosmic rays from molecular clouds by self-generated electric fields

Abstract

It was recently discovered that in some regions of the Galaxy, the cosmic ray (CR) abundance is several orders of magnitude higher than previously thought. Additionally, there is evidence that in molecular cloud envelopes, the CR ionization may be dominated by electrons. We show that for regions with high, electron-dominated ionization, the penetration of CR electrons into molecular clouds is modulated by the electric field that develops as a result of the charge they deposit. We evaluate the significance of this novel mechanism of self-modulation and show that the CR penetration can be reduced by a factor of a few to a few hundred in high-ionization environments, such as those found near the Galactic center.

arXiv commentAccepted by ApJ Letters

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Cited by in corpus (3)

• Constraints on Dark Matter-Electron Scattering from Molecular Cloud Ionization
• Self-discharge by streaming cosmic rays
• Mapping the Cosmic-Ray Ionization Rate in the Local Galaxy with H${}_3^{+}$