The reader has been introduced to a number of topics, taken from Toka- mak research, in order to trace the the development of applications of spec- troscopy in controlled fusion research over the last 35 years, from the early toroidal devices like ZETA to present-day Tokamaks. The subject of plasma spectroscopy has grown in sophistication in terms of the expansion of the atomic processes which have to be considered and their associated data base, the complexity of the experimental techniques and the wide range of diag- nostic applications. Plasma spectroscopy has increased our appreciation of the subtle role of impurities in determining much of the plasma behaviour. Control of impurities, by techniques such as wall conditioning, magnetic divertors, pellet or atomic beam injection and radiation mantles, offers a wealth of future investigations. Acknowledgements The author would like to acknowledge the help and inspiration he has derived from his students past and present in writing this article. In particular he is indebted toM O'Mullane for his technical help in preparing the manuscript and whose research work is featured in the sections on MARFEs and ion transport. References Abbey, A. F., Barnsley, R., Dunn, J., Lea, S. N. and Peacock, N.J.: 1993, UVand X-ray Spectroscopy of Laboratory and Astrophysical Plasmas. (editors, E Silver and S. Khan) Cambridge University Press, 493. Afrosimov, V. V., Gordeev, Y.S. et al.: 1979, J.E. T.P. Lett. 28, 501. Alper, B.: 1995, p.r.ivate communication, JET.

John Dyson has contributed to the study of the hydrodynamic processes that govern a wide variety of astrophysical sources which he has helped explain. In this volume dedicated to him, introductory reviews to a number of the key processes and to the sources themselves are given by leading experts. The mechanisms in which the multi-component natures of media affect their dynamics receive particular attention, but the roles of hydromagnetic effects are also highlighted. The importance of cosmic ray moderation and mass transfer between different thermal phases for cosmic ray moderation and mass transfer between different thermal phases for the evolution of flows are amongst the topics treated. The main types of regions considered include those where starts form, the circumstellar environments of evolved stars, the larger scale interstellar structures caused by the mass loss of stars, and those where the lines of AGNs form.

Molecules in the early Universe acted as natural temperature regulators, keeping the primordial gas cool and, in turn, allowing galaxies and stars to be born. Even now, such similarly simple chemistry continues to control a wide variety of the exotic objects that populate our cosmos. What are the tools of the trade for the cosmic chemist? What can they teach us about the Universe we live in? These are the questions answered in this engaging and informative guide, The Chemically Controlled Cosmos. In clear, non-technical terms, and without formal mathematics, we learn how to study and understand the behaviour of molecules in a host of astronomical situations. We study the secretive formation of stars deep within interstellar clouds, the origin of our own Solar System, the cataclysmic deaths of many massive stars that explode as supernovae, and the hearts of active galactic nuclei, the most powerful objects in the Universe. We are given an accessible introduction to a wealth of astrophysics, and an understanding of how cosmic chemistry facilitates the investigation of many of the most exciting questions concerning astronomy today.

John Dyson has contributed to the study of the hydrodynamic processes that govern a wide variety of astrophysical sources which he has helped explain. In this volume dedicated to him, introductory reviews to a number of the key processes and to the sources themselves are given by leading experts. The book provides a coherent introduction to the astrophysics of diffuse sources suitable for postgraduate students and researchers in astrophysics.

The reader has been introduced to a number of topics, taken from Toka- mak research, in order to trace the the development of applications of spec- troscopy in controlled fusion research over the last 35 years, from the early toroidal devices like ZETA to present-day Tokamaks. The subject of plasma spectroscopy has grown in sophistication in terms of the expansion of the atomic processes which have to be considered and their associated data base, the complexity of the experimental techniques and the wide range of diag- nostic applications. Plasma spectroscopy has increased our appreciation of the subtle role of impurities in determining much of the plasma behaviour. Control of impurities, by techniques such as wall conditioning, magnetic divertors, pellet or atomic beam injection and radiation mantles, offers a wealth of future investigations. Acknowledgements The author would like to acknowledge the help and inspiration he has derived from his students past and present in writing this article. In particular he is indebted toM O'Mullane for his technical help in preparing the manuscript and whose research work is featured in the sections on MARFEs and ion transport. References Abbey, A. F., Barnsley, R., Dunn, J., Lea, S. N. and Peacock, N.J.: 1993, UVand X-ray Spectroscopy of Laboratory and Astrophysical Plasmas. (editors, E Silver and S. Khan) Cambridge University Press, 493. Afrosimov, V. V., Gordeev, Y.S. et al.: 1979, J.E. T.P. Lett. 28, 501. Alper, B.: 1995, p.r.ivate communication, JET.

Introducing astrochemistry to a wide audience, this book describes how molecules formed in chemical reactions occur in a range of environments in interstellar and circumstellar space, from shortly after the Big Bang up to the present epoch. Stressing that chemistry in these environments needs to be driven, it helps identify these drivers and the various chemical networks that operate giving rise to signature molecules that enable the physics of the region to be better understood. The book emphasises, in a non-mathematical way, the chemistry of the Milky Way Galaxy and its planet-forming regions, describes how other galaxies may have rather different chemistries and shows how chemistry was important even in the Early Universe when most of the elements had yet to be formed. This book will appeal to anyone with a general interest in chemistry, from students to professional scientists working in interdisciplinary areas and non-scientists fascinated by the evolving and exciting story of chemistry in the cosmos.

This self-contained introduction to molecular astrophysics is suitable as a text for advanced postgraduate courses on interstellar matter. It is an excellent summary of present knowledge and outstanding questions and will be valued by research astrophysicists, physical chemists, atomic and molecular physicists and atmospheric scientists who wish to become familiar with this field. Descriptions are given of the distributions and types of molecules observed in galactic and extragalactic sources, including those in the vicinity of active galactic nuclei. The chemistry of diffuse and dense clouds is also discussed, and chemical reactions in shocks and dynamically evolving clouds are considered.

Simple chemistry governs a host of the exotic objects that populate our cosmos. For example, molecules in the early Universe acted as natural temperature regulators, keeping the primordial gas cool and, in turn, allowing galaxies and stars to form. What are the tools of the trade for the cosmic chemist and what can they teach us about the Universe we live in? These are the questions answered in this engaging and informative guide--the first book for nonspecialists on molecular astrophysics. In clear, nontechnical terms, and without formal mathematics, Hartquist and Williams show how to study and understand the behavior of molecules in a host of astronomical situations. Readers will learn about the secretive formation of stars deep within interstellar clouds; the origin of our own solar system; the cataclysmic deaths of many massive stars that explode as supernovae; and the hearts of active galactic nuclei, the most powerful objects in the universe. This book provides an accessible introduction to a wealth of astrophysics, and an understanding of how cosmic chemistry allows the investigation of many of the most exciting questions concerning astronomy today.