Observations of pulsar radio emission. I. Total intensity measurements of individual pulses.

The total intensities of individual pulses and subpulses were measured for 16 pulsars by using a multichannel, de-dispersing receiver and the NRAO 300-foot telescope. Some of the data are presented in the form of 'longitude-time diagrams' which display the complex patterns of subpulse intensity variations characteristic of most pulsars. Drifting subpulses are observed and analyzed in several of the sources, but a two-dimensional autocorrelation analysis failed to produce evidence of latent drifting behavior in most of the other pulsars. The separation between adjacent subpulses in the 'drifting subpulse' sources varies approximately inversely as the fourth root of the frequency. Fluctuation statistics are analyzed as a function of pulsar longitude, and cross-correlation analyses show that fluctuations observed in different parts of the pulse window are sometimes, but not always, closely related. These results are consistent with a pulsar model in which the radio emission arises from charged-particle bunches streaming along curved field lines above the pulsar magnetic pole.