Acceleration of UHE Cosmic Ray Particles at Relativistic Jets in   Extragalactic Radio Sources
  A mechanism of ultra-high energy (UHE) cosmic ray acceleration in extragalactic radio sources at the interface between the relativistic jet and the ambient medium is discussed as a supplement to the shock acceleration in `hot spots'. Particles accelerated at the jet side boundary are expected to dominate at highest energies. The spectrum formation near the cut-off energy is modeled using the Monte Carlo particle simulations. 
M. Ostrowski (Astronomical Observatory of the Jagiellonian University)