An incomplete model of RRATs and of nulls mode changes and subpulses

Abstract

A model for pulsars with polar-cap magnetic flux density B antiparallel with spin ω is described. It recognizes the significance of two elementary processes, proton production in electromagnetic showers and photoelectric transitions in ions accelerated through the blackbody radiation field, which must be present at the polar cap in the ω . B < 0 case, but not for pulsars of the opposite spin direction. The two populations are likely to be indistinguishable observationally until curvature radiation pair creation ceases to be possible. The model generates, and provides a physically realistic framework for, the polar-cap potential fluctuations and their time-scales that can produce mode changes and nulls. The rotating radio transients (RRATs) are then no more than an extreme case of the more commonly observed nulls. The model is also able to support the basic features of subpulse drift and to some extent the null-memory phenomenon that is associated with it. Unfortunately, it appears that the most important neutron-star parameter for quantitative predictive purposes is the whole-surface temperature Ts, a quantity which is not readily observable at the neutron-star ages concerned. © 2013 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society.