The Implications of a High Cosmic-Ray Ionization Rate in Diffuse Interstellar Clouds

@article{Indriolo2009TheIO,
  title={The Implications of a High Cosmic-Ray Ionization Rate in Diffuse Interstellar Clouds},
  author={Nick Indriolo and Brian D. Fields and Benjamin J McCall},
  journal={The Astrophysical Journal},
  year={2009},
  volume={694},
  pages={257-267}
}
Diffuse interstellar clouds show large abundances of H+ 3 which can only be maintained by a high ionization rate of H2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high cosmic-ray flux, and a large amount of energy residing in cosmic rays. In this paper, we find that the standard propagated cosmic-ray spectrum predicts an ionization rate much lower than that inferred from H+ 3. Low-energy (~10 MeV) cosmic rays are the most… 

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