APEX-ANTIAPEX ASYMMETRY IN THE ANOMALOUS COSMIC-RAY DISTRIBUTION IN THE HELIOSHEATH

We study the global distribution of low energy anomalous cosmic ray (ACR) protons in the heliosheath within a simplified, axially symmetric model of ACR convective/diffusive transport and loss processes. The ACR diffusion coefficient in the LISM we assume to be significantly larger than inside the heliopause. We take into account the tenser structure of the diffusion coefficient, as far as it is permitted by the assumed axial symmetry. The plasma flow we treat as a fixed background described by Parker's (or related) potential solution. In the heliospheric tail region we include the deviations from incompressible flow (and related upward shift of particles energy) caused by slowing down of the plasma due to charge-exchange with the neutral H background. The results show a pronounced pile-up of the low energy (200 keV-2 MeV) ACR protons in the tail region of the heliosphere. This feature could be detected in the ENA fluxes resulting from transcharging of ACR ions on neutral galactic H background.