Anomalous cosmic rays: Where are they accelerated?

Contrary to some expectations, the spectrum of ACRs did not unfold to a power law when the two Voyager spacecraft crossed the termination shock in December 2004 and August 2007. ACR fluxes continued to increase as Voyagers advanced deeper into the Heliosheath. This can be interpreted in term of the blunt termination shock (TS): because of the shock/magnetic field configuration the time for acceleration was insufficient to reach ACR energies (Kota and Jokipii 2004, McComas and Schwadron 2006). We present 2-D numerical simulations of ACR acceleration at the blunt TS including parallel and perpendicular diffusion. We employ a backward tracing method to explore where and how ACRs are accelerated. We find that seed particles need to be injected near the nose-region to have a good chance to reach ACR energies. Possible interpretations of recent trends in Voyager-1 and -2 particle observations will also be briefly discussed.