Acceleration of galactic and anomalous cosmic rays in the heliosheath

This paper presents a calculation of anomalous and galactic cosmic rays using the particle transport equation with a possible compressional acceleration and second-order Fermi acceleration in the heliosheath in addition to acceleration by the termination shock. Anomalous cosmic-ray flux in the heliosheath should increase with radial distance if the acceleration in the heliosheath is significant. However, both mechanisms cannot produce an upturn bump in the anomalous cosmic-ray spectrum at the termination shock as observed by Voyager 1. The additional accelerations in the heliosheath can also affect galactic cosmic ray modulation, but the radial gradient does not change enough for a clear test of the models.