On the fraction of particles involved in magneto-centrifugally generated ultra-high energy electrons in the Crab pulsar

TL;DR

This paper models how ultra-high energy electrons in the Crab pulsar produce gamma rays and estimates that only a tiny fraction of magnetospheric particles are involved in generating these extreme energies.

Contribution

It provides a quantitative estimate of the fraction of particles involved in ultra-high energy photon production in the Crab pulsar's magnetosphere.

Findings

Ultra-high energy electrons lose energy via quantum synchrotron radiation.

Detected gamma-ray flux limits the involved particle fraction to 4×10⁻⁷.

The process links pulsar magnetospheric activity to observed gamma-ray emissions.

Abstract

The earthward journey of ultra high energy electrons ($\sim 600$ TeV) produced in the Pulsar atmosphere by Landau damping of magneto-centrifugally excited Langmuir waves (drawing energy form the rotational slowdown) on primary electrons, is charted. It is shown, that just as they escape the light cylinder zone, the ultra-high energy particles, interacting with the medium of the Crab nebula, rapidly loose their energy via the quantum synchrotron process, producing highly energetic gamma rays ~ $\sim 0.6$PeV. Interacting with the cosmic background radiation in the interstellar medium, only a tiny fraction of these ultra high energy photons (via the $\gamma\gamma$ channel) are, then transformed into electron-positron pairs. Detected flux of these photons imposes an upper limit on the fraction ($4\times 10^{-7}$) of the magnetospheric particles involved in the process of generation of ultra-high energy photons (up to $600$ TeV).