The 5th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas

Abstract

The 5th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmaswas held in Meudon, France, from August 28 to 31 1995. It was the fifth in a series started by the Atomic SpectroscopicGroup at the University of Lund, Sweden, in 1983. Then followed the meetings in Toledo, USA, Amsterdam, The Nether-lands and Gaithersburg, USA, with a three year period. The original title of the series ended with "... for Astrophysics andFusion Research" and became more general with the 4th colloquium in Gaithersburg.The purpose of the present meeting was, in line with tradition, to bring together "producers" and "users" of atomic dataso as to ensure optimal coordination. Atomic physicists who study the structure of atoms and their radiative and collisionalproperties were invited to explain the development of their work, emphasizing the possibilities of producing precise transition wavelengths and relative line intensities. Astrophysicists and laboratory plasma physicists were invited to review theirpresent research interests and the context in which atomic data are needed.The number of participants was about 70 for the first three meetings, then exploded to 170 at Gaithersburg. About 140participants, coming from 13 countries, attended the colloquium in Meudon. This large gathering was partly due to anumber of participants from Eastern Europe larger than in the past, and it certainly showed a steady interest for interdisciplinary exchanges between different communities of scientists.This volume includes all the invited papers given at the conference and, in the appendix, practical information on accessto some databases. All invited speakers presented their talks aiming at good communication between scientists from different backgrounds. A separate bound volume containing extended abstracts of the poster papers has been published by thePublications de l'Observatoire de Paris, (Meudon 1996), under the responsibility of the same editors.The major trends already apparent during the preceding meetings have been confirmed. The quality of astrophysicalobservations is being continuously improved In particular, the Hubble Space Telescope launched between the third andthe fourth colloquia continues to bring high-resolution data while the Solar Heliospheric Observatory (SOHO) is at thebeginning of its adventure and the Far Ultraviolet Spectroscopic Explorer (FUSE) is expected. Astrophysicists interested insolar or stellar atmospheres are facing new diagnostic problems concerning line broadening and deviation from localthermodynamic equilibrium (LTE). Studies of laboratory plasma like X-ray lasers and fusion plasma are still demandingmore atomic data, for instance for problems related to a tokamak divertor in the future International ThermonuclearExperimental Reactor (ITER). The need for atomic data in the interpretation of the new observations constitutes a stimulating challenge for atomic physicists. Theoreticians not only continue to improve the description of atomic structureincluding relativistic and nuclear hyperhe effects, but also carry out methodological developments, such as global andstatistical approaches. They are able, using up-to-date computational techniques, to produce large amounts of data and areorganising these data in user-friendly computerised databases. Results of systematic calculations (such as the OpacityProject) now are being exploited for modelling. A new tool for plasma diagnostics is proposed via the polarisation of X-rayemission. On the experimental side, novelties of the last decade like the Electron Beam Ion Trap and the VW Fouriertransform spectrometer are fully operational. Emission measurements and the combination of atomic beam and lasertechniques proved to be complementary and fruitful for lifetime determinations. Efforts are made by atomic physicists toestimate the precision of measured or calculated data released.Laboratory spectroscopy and astronomy have a long common history. Indeed, we are reminded that a century ago,terrestrial and solar helium were identified with one another through spectral lines, while recent studies of nebulae and theinterstellar medium provide nice examples of the continuing interplay between spectroscopy and astrophysical models.During the Amsterdam meeting, some astrophysicists deplored that the so-called "traditional term analysis" was disappearing. They should be reassured about the near future owing to three invited papers and a great number of posters onthis type of work.We are grateful to the members of the Scientific Committee who helped us to set up the scientific programme and to allthe referees who reviewed the manuscripts published in this volume. We thank the Observatoire de Paris-Meudon, theCentre National de la Recherche Scientifique and the Centre National d'Etudes Spatiales for financial support. We alsothank the Ministère de l'Education Nationale, de l'Enseignement Supérieur, de la Recherche et de l'Insertion Professionnelle, the National Aeronautics and Space Administration and the Laboratoire Aimé Cotton for providing travel grants, Further support from SUN Microsystems, Alcatel and Crédit Lyonnais is gratefully acknowledged. The colloquiumgreatly benefited from the infrastructure of the Observatoire de Paris-Meudon and the cooperation of its staff, especiallymembers of the Département Atomes, Molécules en Astrophysique (DAMAp).The 6th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and LaboratoryPlasmas is scheduled to be held in Victoria, Canada in 1998.