This discussion is concerned with the production of cosmic rays in supernova explosions. In particular, we are discussing the role of pulsars (which we all believe to be neutron stars) in this process. I should like first to recall that (so far as I am aware) the idea that neutron stars form in supernova explosions, and that this phenomenon is relevant to cosmic rays, was first proposed by Baade and Zwicky in 1934. The argument was originally based on energy considerations, and further estimates indicated that supernovae could indeed be the main source of cosmic rays (ter Haar, 1950). When radioastronomical data later showed that supernova remnants definitely contained large numbers of relativistic electrons, there could be no doubt that they were sources of cosmic rays as well (and it became quite probable that they were indeed the major source of such particles). The growth of these ideas can be studied in historical perspective in Rosen’s (1969) compilation of papers on cosmic ray origin theories. As is so often the case, this subject has developed in a cyclic and repetitious fashion. I wish to make this point because I feel that my own contribution to these theories has sometimes been overestimated - though I hope I cannot myself be blamed for this.

It would not be appropriate to consider cosmic ray origins in detail during this discussion. I have in my case given my present views elsewhere (Ginzburg, 1969, 1970). The following remarks will deal specifically with the role of pulsars.