It is argued that both observations and theory indicate that radiation damping plays an important rôle in pulsar emission. The two-mode behavior as well as the observed value of the brightness temperature can both be understood as a result of radiation damping. In this context, a possible cause for the enhanced depolarization in the wings of pulsar profiles is discussed.

We present 430-M Hz Arecibo single pulse polarization measurements for PSR 2303+30. Single pulses typically consist of one or two subpulses. Each subpulse is associated with circular polarization which reverses sense near the subpulse peak and with its own swing of the position angle which does not coincide with the average position-angle curve. We attempt to explain these complicated characteristics within the framework of a coherent curvature radiation model of pulsar emission.

One of the important problems in pulsar studies is to determine the magnetic inclination angle α, the intrinsic width of the radiation beam (2ρ) and the angle (α + β) between the observer's direction and the rotation axis. In this paper we solve this problem for individual pulses by using the observed pulse width (2Δ𝜙), the swing of polarization angle (2Δψ), and its central gradient (dψ/d𝜙)max.

From the polar cap model we establish three basic geometrical relations, a complete set of equations from which explicit solutions can be obtained using the observed data. This is the first time that the orientation of pulsar emission is solved analytically solely on the basis of a geometrical model. However, the results are shown to be sensitively connected to the polarization-angle swing (2Δψ), which is not well measured for most pulsars. So the number of pulsars to which our method can be applied is limited. The importance of the measurement of Δψ is seen from our method. To ensure the credibility of our results, we have discussed the conditions to be satisfied by all reliable pulsar measurements. Our method is shown to be more favorable for pulsars with large pulse width 2Δ𝜙, large central gradient (dψ/d𝜙)max and large magnetic inclination angle α. Out of 120 pulsars (from Lyne and Manchester 1988), 40 are solvable, and 7 are believed to be reliable. We discuss our method for the determination of pulsar geometry in comparison with other methods.

I've been asked to summarize my impressions of where pulsar theory stands, in general, from the point of view of this conference. I've organized these comments from two distinct points of view: that of a prototypical observer and that of a prototypical theorist. These comments are not necessarily “fair” but have been exaggerated to make a point.

Many of the problems discussed at this conference were also on the agenda of the Bonn symposium on pulsars (IAU 95) about ten years ago, and it seems worthwhile to compare how our view of the magnetosphexe and pulsar emission has changed since then.

During the course of this colloquium many papers have been presented on observational aspects of pulsar astronomy. In the following discussion I have not attempted to be comprehensive but have selected a number of areas of interest to me.

The basic pulsar properties appear to be consistent over the full range of pulsar periods from 1 ms to 4s, implying that the emission mechanism is the same for all pulsars. There was a general consensus among the observers that the radio emission occurs low down in the pulsar's magnetosphere above the magnetic polar region.

Though it had been circulating through the grapevine for more than ten years, it is now widely known that the ion work function on the neutronstar surface is so low that the surface may not even be a solid (Kössl et al. 1988). In this meeting the issue surfaced in the review by Arons, and came up in many discussions by the participants. A view was expressed that since a real “professional” calculation is not yet available, one should reserve judgement on this issue. However, three different methods lead to about the same value, a fraction of a keV, for the ion work function. Furthermore, the polar cap region in pulsars will be hot and will have strong electromagnetic fields. Thus easy extraction of ions from the stellar surface appears most likely.