Pulsar Microstructure: Periodicities, Polarization and Probes of Pulsar Magnetospheres

Abstract

This paper discusses characteristic time scales, periodicities and polarization of microstructure in pulsar signals. The relationship of microstructure polarization to the polarization of subpulses and the average profile is analysed in detail for PSR2016+28. For this pulsar the contributions of micropulses to the variance of the intensity vary with radio frequency v approximately as V-I and the characteristic time scale varies as v-a, with 0·2 ;S IX ;S 0·3. In summarizing possible interpretations of microstructure, we distinguish between angular beaming and temporal modulation processes that can cause intensity variations. We outline, with regard to the frequency dependence of pulse structure, how micropulses can be used to probe the depth and variability of the emission region.