CRAFT (Cosmic Ray Acceleration From Turbulence) in Molecular Clouds
  Low-energy cosmic rays, in particular protons with energies below 1 GeV, are
significant drivers of the thermochemistry of molecular clouds. However, these
cosmic rays are also greatly impacted by energy losses and magnetic field
transport effects in molecular gas. Explaining cosmic ray ionization rates of
$10^{-16}$ s$^{-1}$ or greater in dense gas requires either a high external
cosmic ray flux, or local sources of MeV-GeV cosmic ray protons. We present a
new local source of low-energy cosmic rays in molecular clouds: first order
Fermi-acceleration of protons in regions undergoing turbulent reconnection in
molecular clouds. We show from energetic-based arguments there is sufficient
energy within the magneto-hydrodynamic turbulent cascade to produce ionization
rates compatible with inferred ionization rates in molecular clouds. As
turbulent reconnection is a volume-filling process, the proposed mechanism can
produce a near-homogeneous distribution of low-energy cosmic rays within
molecular clouds.
