Introduction To Solar Radio Astronomy And Radio Physics

1. 1. Short History of Solar Radio Astronomy Since its birth in the forties of our century, solar radio astronomy has grown into an extensive scientific branch comprising a number of quite different topics covering technical sciences, astrophysics, plasma physics, solar-terrestrial physics, and other disciplines. Historically, the story of radio astronomy goes back to the times of James Clerk Maxwell, whose well known phenomenological electromagnetic field equations have become the basis of present-time radio physics. As a direct consequence of these equations, Maxwell was able to prognosticate the existence of radio waves which fifteen years later were experimentally detected by the famous work of Heinrich Hertz (1887/88). However, all attempts to detect radio waves from cosmic objects failed until 1932, which was mainly due to the early stage of development of receiving techniques and the as yet missing knowledge of the existence of a screening ionosphere (which was detected in 1925). Therefore, famous inventors like Thomas Edison and A. E. Kennelly, as well as Sir Oliver Lodge, were unsuccessful in receiving any radio emission from the Sun or other extraterrestrial sources. Another hindering point was that nobody could a priori expect that solar radio emission should have something to do with solar activity so that unfortunately by chance some experiments were carried out just at periods of low solar activity. This was also why Karl Guthe Jansky at the birth of radio astronomy detected galactic radio waves but no emission from the Sun.

For over 35 years, radio astronomical techniques have made an impressive series of advances in our understanding of solar phenomena. However, although the subject has been partially discussed in "Paris Symposium on Radio Astronomy" in 1958, NASA-GSFC Symposium on "Physics of Solar Flares" in 1963, and the lAU Symposium No. 57 on "Coronal Disturbances" in 1973, there has not been a major international meeting dedicated to "Radio Physics of the Sun". This is the first major symposium on the subject held under the auspices of the International Astronomical Union. It was jointly spon sored by lAU Commission 40, Radio Astronomy, and by lAU Commission 10, Solar Activity. It was also sponsored by the Solar Physics Division of the American Astronomical Society. Thig volume contains the proceedings of this meeting, lAU Symposium No. 86 on "Radio Physics of the Sun" that was held in College Park, Maryland, August 7-10, 1979. The Scientific Organizing Committee of the Symposium consisted of M. R. Kundu (chairman), G. A. Dulk, O. Hachenberg, M. Kuperus, D. J. McLean, D. Melrose, M. Pick, J. L. Steinberg, T. Takakura, A. Tlamicha and V. V. Zheleznyakov. The topics and speakers were chosen in order to emphasize the current observational material with particular reference to centi meter wavelength observations of a few arc-second resolution, fast two-dimensional pictures of the sun at meter-decameter wavelengths and the recent advances in plasma and radiation theory.

Radio astronomy is an active and rapidly expanding field due to advances in computing techniques, with several important new instruments on the horizon. This text provides a thorough introduction to radio astronomy and its contribution to our understanding of the universe, bridging the gap between basic introductions and research-level treatments. It begins by covering the fundamentals physics of radio techniques, before moving on to single-dish telescopes and aperture synthesis arrays. Fully updated and extensively rewritten, the fourth edition places greater emphasis on techniques, with detailed discussion of interferometry in particular, and comprehensive coverage of digital techniques in the appendices. The science sections are fully revised, with new author Peter N. Wilkinson bringing added expertise to the sections on pulsars, quasars and active galaxies. Spanning the entirety of radio astronomy, this is an engaging introduction for students and researchers approaching radio astronomy for the first time.

This volume is the outgrowth of several international meetings to discuss a vision for the future of solar radio physics: the development of a new radio instrument. From these discussions, the concept for the Frequency Agile Solar Radiotelescope (FASR) was born. Most of the chapters of this book are based oninvitedtalksattheFASRScienceWorkshop,heldinGreenbank,WVinMay 2002, and a special session on Solar and Space Weather Radiophysics held at the 200th American Astronomical Society meeting held in Albuquerque, NM in June 2002. Although many of the chapters deal with topics of interest in planning for FASR, other topics in Solar and Space Weather Radiophysics, such as solar radar and interplanetary scintillation, are covered to round out the discipline. The authors have been asked to write with a tutorial approach, to make the book useful to graduate students and scientists new to radio physics. This book is more than a compilation of FASR science topics. The FASR instrument concept is so revolutionary—by extending capability by an order of magnitude in several dimensions at once (frequency coverage, spatial reso- tion,dynamicrange,timeresolution,polarizationprecision)—thatitchallenges scientiststothinkinnewways. Theauthorsofthefollowingchaptershavebeen taskednotonlywithreviewingthecurrentstateofthe?eld,butalsowithlooking to the future and imagining what is possible. Radio emission is extremely complex because it is generated so readily, and every imaginable plasma parameter affects it. This is both its great strength and its weakness.

Designed for a course in radio astronomy or for use as a reference for practicing engineers and astronomers, this book provides a comprehensive overview of the topic. Application boxes in each chapter cover topics like LOFAR, DSN, and VLBI. The book begins with the history of radio astronomy, then explains the fundamentals, polarization, designing radio telescopes, understanding radio arrays, interferometers, receiving systems, mapping techniques, image processing and propagation effects in relation to radio astronomy. A special chapter in the end presents the GMRT radio array as an example of the explained techniques. Features: •Includes context-connection boxes, including NASA’s Deep Space Network (DSN) the South Pole Telescope (SPT), the Low-Frequency Array (LOFAR), Space Very Long Baseline Interferometry (VLBI), pulsar dispersion and distance, and plane waves in conducting and dielectric media •Contains several appendices including radiation potential formalism, the physics of radio spectral lines, and a table of world radio observatories •View the comprehensive companion disc with hundreds of color images and figures from the text

For over 35 years, radio astronomical techniques have made an impressive series of advances in our understanding of solar phenomena. However, although the subject has been partially discussed in "Paris Symposium on Radio Astronomy" in 1958, NASA-GSFC Symposium on "Physics of Solar Flares" in 1963, and the lAU Symposium No. 57 on "Coronal Disturbances" in 1973, there has not been a major international meeting dedicated to "Radio Physics of the Sun". This is the first major symposium on the subject held under the auspices of the International Astronomical Union. It was jointly spon sored by lAU Commission 40, Radio Astronomy, and by lAU Commission 10, Solar Activity. It was also sponsored by the Solar Physics Division of the American Astronomical Society. Thig volume contains the proceedings of this meeting, lAU Symposium No. 86 on "Radio Physics of the Sun" that was held in College Park, Maryland, August 7-10, 1979. The Scientific Organizing Committee of the Symposium consisted of M. R. Kundu (chairman), G. A. Dulk, O. Hachenberg, M. Kuperus, D. J. McLean, D. Melrose, M. Pick, J. L. Steinberg, T. Takakura, A. Tlamicha and V. V. Zheleznyakov. The topics and speakers were chosen in order to emphasize the current observational material with particular reference to centi meter wavelength observations of a few arc-second resolution, fast two-dimensional pictures of the sun at meter-decameter wavelengths and the recent advances in plasma and radiation theory.

In this comprehensive review of the radio astronomy of the Sun, thirteen researchers based in Australia summarise our present knowledge of solar radio emission at wavelengths of about one metre. CSIRO scientists have been at the forefront of research in solar radiophysics for thirty years; the historical review of J. Paul Wild is, therefore, highly appropriate. Introductory sections give the history of the subject and outline basic physical principles. Instrumental techniques are described next, to set the scene for the classification of bursts, flare phenomena, and the propagation of radio waves through the corona. In the second half of the book there is a thorough description of burst types, solar storms, and the Quiet Sun.

This translation of A Brief History of Radio Astronomy in the USSR makes descriptions of the antennas and instrumentation used in the USSR, the astronomical discoveries, as well as interesting personal backgrounds of many of the early key players in Soviet radio astronomy available in the English language for the first time. This book is a collection of memoirs recounting an interesting but largely still dark era of Soviet astronomy. The arrangement of the essays is determined primarily by the time when radio astronomy studies began at the institutions involved. These include the Lebedev Physical Institute (FIAN), Gorkii State University and the affiliated Physical-Technical Institute (GIFTI), Moscow State University Sternberg Astronomical institute (GAISH) and Space Research Institute (IKI), the Department of Radio Astronomy of the Main Astronomical Observatory in Pulkovo (GAO), Special Astrophysical Observatory (SAO), Byurakan Astrophysical Observatory (BAO), Crimean Astrophysical Observatory, Academy of Sciences of the Ukraine (SSR), Institute of Radio Physics and Electronics of the USSR Academy of Sciences (IRE), Institute of Terrestrial Magnetism, the Ionosphere and Radio-Wave Propagation Institute (IZMIRAN), Siberian Institute of Terrestrial Magnetism, the Ionosphere and Radio-Wave Propagation (SibIZMIRAN), the Radio Astrophysical Observatory of the Latvian Academy of Sciences and Leningrad State University. A Brief History of Radio Astronomy in the USSR is a fascinating source of information on a past era of scientific culture and fields of research including the Soviet SETI activities. Anyone interested in the recent history of science will enjoy reading this volume.