This book is the result of a meeting held in August, 1986 in Irsee, West Germany. As the title suggests, the aim of the meeting was to discuss physical processes in interstellar clouds, determine the current status, aims and future direction of the research in this area. Interstellar clouds contain nearly all the mass of diffuse gas in our galaxy, some 10% of the total galactic mass. They represent the birth site for stars and the final "dumping ground" for matter ejected from stars (winds, ex- plosive ejecta) and thus play an integral part in the galactic recycling of material. Not only are the clouds important for the structure and evolution of our galaxy, they are also interesting objects of study "per se". Because of their vast scales (up to about 100 parsec), extreme temperatures (as low as about lOOK), and long life 8 times (estimated a about 10 years) a number of physical and chemical processes occur in these environments, which we are not able to study elesewhere, certainly not in laboratories. It is for this reason that the meeting, and hence this book, was organized in such a way that firstly the latest observational results were sum- m~ized, going from the global, large scales, to finer details and dynamics, then progressing onwards to the processes -dynamical, chemical, electromagnetic, etc.
` ..provides an excellant overview of interstellar cloud physics with descriptions of practically all areas where advances are currently being made. '
Formation and Evolution of the Largest Cloud Complexes in Spiral Galaxies.- Diffuse Interstellar Gas.- The Structure of Molecular Clouds.- Structure and Physics of Cool Giant Molecular Complexes.- Galactic Gamma Rays and Gas Tracers.- The Distribution of Molecular Gas in the Galaxy.- Gamma Rays and the Distribution of Cosmic Rays in the Galaxy.- Supernovae and the Interstellar Medium.- Energy Dissipation in Magnetic Cloud Complexes.- The Large-scale Motion of the ISM and the Interaction with the System of Stars.- Fluctuations in the ISM due to the Gravitational Interaction with the System of Stars.- Dense Cores in Dark Clouds.- Molecular Cloud Temperature and Density Determinations and What They Teach Us.- Formation and Heating of Molecular Cloud Cores.- Fragmentation and Turbulence in Molecular Clouds.- Observational Constraints on Cloud Physics.- Chemical Processes in the Interstellar Gas.- The Abundance of Interstellar CO.- Dust Formation in Stellar Winds.- Infrared Emission from Interstellar PAHs.- Evolution of Interstellar Dust.- The Role of Dust in Interstellar Chemistry.- The Effects of Dust on the Ionization Structures and Dynamics in Magnetized Clouds.- Structural Features and Scattering Properties of Dust Particles.- MHD Shock Waves in Diffuse Molecular Clouds.- Interstellar Magnetic Fields.- Star Formation in Magnetic Interstellar Clouds: 1.Interplay between Theory and Observations.- Star Formation in Magnetic Interstellar Clouds: 2.Basic Theory.