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(Abridged)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 (UHECR) acceleration due to drifts in magnetized, cylindrically collimated, sheared jets of powerful active galaxies (with jet luminosity $geq 10^{46}$ erg s$^{-1}$). We point out that a positively charged particle carried by such a plasma is in an unstable equilibrium if ${bf B} cdot abla times {bf v}< 0$, so that kinetic drift along the velocity shear would lead to fast, {it regular} energy gain. We show that if a seed of pre-accelerated particles with energy below the ankle $leq 10^{18}$ eV is present, these particles can be boosted to energies above $ 10^{19}$ eV. A key feature of the mechanism is that the highest rigidity particles are accelerated most efficiently implying the dominance of light nuclei for energies above the ankle in our model: from a mixed population of pre-accelerated particle the drift mechanism picks up and boosts protons preferably. In addition, after a particle traversed large fraction of the available potential, its Larmor radius becomes of the order of the jet thickness. In this case, {it the maximum possible acceleration rate of inverse relativistic gyro-frequency is achieved} and a particle finally become unconfined and leave the jet.
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 (UHECR) acceleration due to drifts in magnetized, c
We present six case studies from a broad mass range ($1 - 10^9$ $M_odot$) of astrophysical objects, each of which exhibit signs of jets and emit intense high energy gamma rays ($>10$ GeV). Many of these objects also emit spatially identifiable ultra
In this paper, we investigate the acceleration in relativistic jets of high-energy proton preaccelerated in the magnetosphere of a supermassive black hole. The proton reaches maximum energy when passing the total potential difference of $U$ between t
The highest energy cosmic rays could be produced by drifts in magnetized, cylindrically collimated, sheared jets of powerful active galaxies (i.e. FR II radiogalaxies; radio loud quasars and high power BL Lacs). We show that in such scenarios proton
In this chapter, we review some features of particle acceleration in astrophysical jets. We begin by describing four observational results relating to the topic, with particular emphasis on jets in active galactic nuclei and parallels between differe