The dynamic behavior is governed by the adiabatic index, which in turn depends on the physical state of the stellar interior. The eigenfrequencies of the lowest radial modes of linear, adiabatic pulsations are calculated. Stability of protoneutron stars with respect to small radial perturbations is studied, and the validity of the static stability criteria is discussed. The pulse profile is complex with many identifiable features, including an unusual double notch, and evolves strongly with frequency. Strong linear and circular polarization are observed at all frequencies, with the fractional linear polarization highest near the wings of the pulse.
Circular polarization is strongest near the pulse center, with a sense reversal at the center.
However, at other frequencies, some of these transitions are not orthogonal. Even when these transitions are allowed for, the position angle does not follow the simple rotating-vector model, suggesting departures from a dipole field configuration in the emission region. This effect has not previously been seen in any pulsar. An improved value of the rotation measure along the path to the pulsar is derived. Measurement of scatter broadening for 27 pulsars at 327 MHz New measurements of scattering delay for 27 pulsars at 327 MHz are presented.