A Constraint on Electromagnetic Acceleration of Highest Energy Cosmic Rays

Authors:
Mikhail V. Medvedev

Comments: 5 pages, 2 figures. Accepted for publication in PRE

The energetics of electromagnetic acceleration of ultra-high-energy cosmic
rays (UHECRs) is constrained both by confinement of a particle within an
acceleration site and by radiative energy losses of the particle in the
confining magnetic fields. We demonstrate that the detection of ~ 3 x 10^{20}
eV events is inconsistent with the hypothesis that compact cosmic accelerators
with high magnetic fields can be the sources of UHECRs. This rules out the most
popular candidates, namely spinning neutron stars, active galactic nuclei
(AGNs), and gamma-ray burst blast waves. Galaxy clusters and, perhaps, AGN
radio lobes remain the only possible (although not very strong) candidates for
UHECR acceleration sites. Our analysis places no limit on linear accelerators.
With the data from the future Auger experiment one should be able to answer
whether a conventional theory works or some new physics is required to explain
the origin of UHECRs.

References and citations for this submission:

SLAC-SPIRES HEP (refers to ,
cited by, arXiv reformatted)