Ultra High Energy Electrons Powered by Pulsar Rotation

Abstract

A new mechanism of particle acceleration to ultra high energies, driven by the rotational slow down of a pulsar (Crab pulsar, for example), is explored. The rotation, through the time dependent centrifugal force, can very efficiently excite unstable Langmuir waves in the e-p plasma of the star magnetosphere via a parametric process. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV ($\sim 100$ TeV) and even PeV energy domain. It is expected that the proposed mechanism may, partially, unravel the puzzle of the origin of ultra high energy cosmic ray electrons.