The production and acceleration mechanisms of ultrahigh-energy cosmic rays (UHECRs) of
energy> 10 20 eV, clearly beyond the GZK cutoff limit, remain unclear, which points to the …

We develop a model of ultra-high energy cosmic ray (UHECR) production via acceleration in
a rotation-induced electric field in vacuum gaps in the magnetospheres of supermassive …

The origin of ultrahigh-energy cosmic rays (UHECRs) is a half-century-old enigma. The
mystery has been deepened by an intriguing coincidence: over ten orders of magnitude in …

In the first part of this review we discuss the basic observational features at the end of the
cosmic ray (CR) energy spectrum. We also present there the main characteristics of each of …

Abstract The Auger Collaboration reports (Auger Collaboration 2007 Science 318 939, The
Pierre Auger Collaboration 2008 Astropart. Phys. 29 188) that the arrival directions of≳ 60 …

We propose that ultra-high-energy (UHE) cosmic rays (CRs) above 10 18 eV are produced
in relativistic jets of powerful active galactic nuclei via an original mechanism, which we dub" …

We review open questions and prospects for progress in ultrahigh-energy cosmic ray
(UHECR) research, based on a series of discussions that took place during the “The High …

We demonstrate that a population of active galactic nuclei (AGN) can describe the observed
spectrum of ultra-high-energy cosmic rays (UHECRs) at and above the ankle, and that the …

We review basic constraints on the acceleration of ultra-high-energy (UHE) cosmic rays
(CRs) in astrophysical sources, namely, the geometric (Hillas) criterion and the restrictions …

In this review we discuss the important progress made in recent years towards
understanding the experimental data on cosmic rays with energies≳ 1019 eV. We begin …