Low-energy cosmic rays in the Orion region

The recently observed nuclear gamma-ray line emission from the Orion complex implies a high flux of low-energy cosmic rays (LECR) with unusual abundance. This cosmic ray component would dominate the energy density, pressure, and ionising power of cosmic rays, and thus would have a strong impact on the general structure of the interstellar medium. We propose an independent test for the existence of LECR by observing the inverse bremsstrahlung and secondary bremsstrahlung of these nucleons. The expected X-ray photon flux scales to the gamma-ray photon flux with the ratio of the corresponding cross sections, thus it depends only weakly on the LECR spectrum and not on any other parameter. Observations with HEPC will allow us to derive the bremsstrahlung spectrum over the weakly extended gamma-ray emission regions.