This course-tested textbook conveys the fundamentals of magnetic fields and relativistic plasma in diffuse cosmic media, with a primary focus on phenomena that have been observed at different wavelengths. Theoretical concepts are addressed wherever necessary, with derivations presented in sufficient detail to be generally accessible. In the first few chapters the authors present an introduction to various astrophysical phenomena related to cosmic magnetism, with scales ranging from molecular clouds in star-forming regions and supernova remnants in the Milky Way, to clusters of galaxies. Later chapters address the role of magnetic fields in the evolution of the interstellar medium, galaxies and galaxy clusters. The book is intended for advanced undergraduate and postgraduate students in astronomy and physics and will serve as an entry point for those starting their first research projects in the field.

This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.

This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.

This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.

While magnetic fields permeate the universe on all scales, the present book is dedicated to their investigation on the largest scales and affords a balanced account of both theoretical and observational aspects. Written as a set of advanced lectures and tutorial reviews that lead up to the forefront of research, this book offers both a modern source of reference for the experienced researchers as well as a high-level introductory text for postgraduate students and nonspecialist researchers working in related areas.

This self-contained introduction to astrophysical magnetic fields provides a comprehensive review of the current state of the field and a critical discussion of the latest research. Its emphasis on results that are likely to form the basis for future progress benefits a broad audience of advanced students and active researchers.

Magnetism, when extended beyond normal frameworks into cosmic space is characterized by an enormous spatial scale. Because of their large sizes the nature of magnets such as the Earth and the Sun is entirely different from the nature of a horseshoe magnet. The source of cosmic magnetism is associated with the hydrodynamic motions of a highly conductive medium. In this aspect, cosmic magnets resemble a dynamo. However, currents in the dynamo flow along properly ordered wires, while chaotic, turbulent motions are dominant inside stars and liquid planetary cores. This makes more intriguing and surprising the fact that these motions maintain a regular magnetic field. Maintenance of magnetic fields is even more impressive in huge magnets, i.e. galaxies. In fact, we are living inside a giant dynamo machine, the Milky Way galaxy. Although the idea of the global magnetic field of our Galaxy was clearly proposed almost 40 years ago, firm observational evidence and definite theoretical concepts of galactic magnetism have been developed only in the last decade. This book is the first attempt at a full and consistent presentation of this problem. We discuss both theoretical views on the origin of galactic magnetism and the methods of observational study. Previous discussions were on the level of review articles or separate chapters in monographs devoted to cosmic magnetic fields (see, e.g., H. K. Moffatt, 1978, E. N. Parker, 1979 and Zeldovich et aI., 1983).