Exclusion of Cosmic Rays from Molecular Clouds by Self-generated Electric Fields

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 wit...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2020-10, Vol.902 (1), p.L25
Main Authors: Silsbee, Kedron, Ivlev, Alexei V.
Format: Article
Language:English
Subjects:
Clouds
Cosmic rays
Electric fields
Electrons
Galactic cosmic rays
Galaxies
Interstellar medium
Interstellar plasma
Ionization
Molecular clouds
Penetration
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Summary: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.
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/abbc20