The idea to hold a conference on the Evolution of Close-Binary X-ray sources grew in the summer of 1984. At that time we were hoping that some new results would be harvested in the months to come which would stimulate further work. We were particularly looking towards the Euro pean X-ray Observatory, EXOSAT, for new contributions. How lucky we were; quite unexpected developments took place. Just prior to the conference, quasi-periodic oscillations (now known as QPO) were discovered in three bright low-mass X-ray binaries: GX 5-1, Sco X-1, and Cyg X-2. They played an important role at the meeting. The possibility that QPOs imply a neutron star magnetic dipole field, and a neutron star rotation period in the millisecond range, received a lot of attention. This is not surprising, as it lends support to the idea, suggested earlier, that the 6-msec binary radio pulsar PSR 1953+29 evolved from a stage in which it was a bright low-mass X-ray binary. There was special interest in the possibility of white dwarf collapse into a neutron star. This is a. particularly attractive way to form the bright low-mass X-ray binaries, often referred to as galactic bulge sources. It would allow for the possibility of a very young neutron star in a very old binary system. The relatively high magnetic fields that one could infer from QPO could then be explained."

Gas at temperatures exceeding one million degrees is common in the Universe. Indeed it is likely that most of the gas in the Universe exists in intergalactic space in this form. Such highly-ionized gas, or plasma, is not restricted to the rarefied densities of intergalactic space, but is also found in clusters of galaxies, in galaxies themselves, in the expanding remnants of exploded stars and at higher densities in stars and the collapsed remains of stars up to the highest densities known, which occur in neutron stars. The abundant lower-Z elements, at least, in such gas are completely ionized and the gas acts as a highly conducting plasma. It is therefore subject to many cooperative phenomena, which are often complicated and ill-understood. Many of these processes are, however, well-studied (if not so well-understood) in laboratory plasmas and in the near environment of the Earth. Astronomers therefore have much to learn from plasma physicists working on laboratory and space plasmas and the parameter range studied by the plasma physicists might in turn be broadened by contact with astronomers. With that in mind, a NATO Advanced Research Workshop on Physical Processes in Hot Cosmic Plasmas was organized and took place in the Eolian Hotel, Vulcano, Italy on May 29 to June 2 1989. This book contains the Proceedings of that Workshop.

The idea to hold a conference on the Evolution of Close-Binary X-ray sources grew in the summer of 1984. At that time we were hoping that some new results would be harvested in the months to come which would stimulate further work. We were particularly looking towards the Euro pean X-ray Observatory, EXOSAT, for new contributions. How lucky we were; quite unexpected developments took place. Just prior to the conference, quasi-periodic oscillations (now known as QPO) were discovered in three bright low-mass X-ray binaries: GX 5-1, Sco X-1, and Cyg X-2. They played an important role at the meeting. The possibility that QPOs imply a neutron star magnetic dipole field, and a neutron star rotation period in the millisecond range, received a lot of attention. This is not surprising, as it lends support to the idea, suggested earlier, that the 6-msec binary radio pulsar PSR 1953+29 evolved from a stage in which it was a bright low-mass X-ray binary. There was special interest in the possibility of white dwarf collapse into a neutron star. This is a. particularly attractive way to form the bright low-mass X-ray binaries, often referred to as galactic bulge sources. It would allow for the possibility of a very young neutron star in a very old binary system. The relatively high magnetic fields that one could infer from QPO could then be explained."