Particle dynamics in relativistic sheared layers and acceleration of Ultra High Energy Cosmic Rays

Relativistic outflows carrying large scale magnetic fields have large inductive potential and may accelerate protons to ultra high energies. We discuss a novel scheme of Ultra-High Energy Cosmic Ray acceleration due to drifts in magnetized, cylindrically collimated, sheared jets of powerful active galaxies. A proton carried by such a plasma is in an unstable equilibrium if ${\bf B} \cdot \nabla \times {\bf v}< 0$, so that kinetic drift along the velocity shear would lead to fast, {\it regular} energy gain. Acceleration rate {\it increases} with energy reaching at highest energies the absolute theoretical maximum of inverse relativistic gyro-frequency.