Ultra High Energy Electrons Powered by Pulsar Rotation

TL;DR

This paper proposes a novel mechanism where pulsar rotation induces Langmuir waves that accelerate electrons to ultra high energies, potentially explaining the origin of ultra high energy cosmic ray electrons.

Contribution

It introduces a new particle acceleration process driven by pulsar rotation and plasma wave interactions, providing a plausible explanation for ultra high energy electrons.

Findings

Electromagnetic waves are excited by pulsar rotation via a parametric process.

Electrons are accelerated to energies up to 100 TeV and PeV levels.

The mechanism is particularly applicable to the Crab pulsar.

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.