Fermi Pulsars and the Cosmic Ray Knee

Abstract

Nuclei, if lifted into the radiation zone of a weak axisymmetric pulsar, are accelerated to quasi-monoenergetic spectrum, with more than half of the nuclear luminosity emitted nearly monoenergetically, at the energy E approximately = 4Ze(L/c)^(1/2), where L is the spin-down power. With a number of (not obviously wrong) assumptions, this turns Fermi (-like) weak pulsars into prominent accelerators at energies near the cosmic ray knee. The main uncertainty is purely theoretical: one needs to understand if nuclei are major positive charge carries in some weak pulsar magnetospheres.