The International Astronomical Union is a non-governmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation. It was founded in 1919 and is based in Paris, France.
The ionosphere is the ionized part of the upper atmosphere of Earth, from about 48 km (30 mi) to 965 km (600 mi) above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. It also affects GPS signals that travel through this layer.
The International Geophysical Year, also referred to as the third International Polar Year, was an international scientific project that lasted from 1 July 1957 to 31 December 1958. It marked the end of a long period during the Cold War when scientific interchange between East and West had been seriously interrupted. Sixty-seven countries participated in IGY projects, although one notable exception was the mainland People's Republic of China, which was protesting against the participation of the Republic of China (Taiwan). East and West agreed to nominate the Belgian Marcel Nicolet as secretary general of the associated international organization.
Lloyd Viel Berkner was an American physicist and engineer. He was one of the inventors of the measuring device that since has become standard at ionospheric stations because it measures the height and electron density of the ionosphere. The data obtained in the worldwide net of such instruments were important for the developing theory of short wave radio propagation to which Berkner himself gave important contributions.
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1mm, which is shorter than the diameter of a grain of rice. At 30 Hz the corresponding wavelength is ~10,000 kilometers, which is longer than the radius of the Earth. Wavelength of a radio wave is inversely proportional to its frequency, because its velocity is constant. Like all electromagnetic waves, radio waves in a vacuum travel at the speed of light, and in the Earth's atmosphere at a slightly slower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects, and are part of the blackbody radiation emitted by all warm objects.
The radio window is a range of frequencies of electromagnetic radiation that penetrate the Earth's atmosphere. Typically, the lower limit of the radio window's range has a value of about 10 MHz ; the best upper limit achievable from optimal terrestrial observation sites is equal to approximately 1 THz.
In physics, absorption of electromagnetic radiation is how matter takes up a photon's energy — and so transforms electromagnetic energy into internal energy of the absorber.
The Committee on Space Research (COSPAR) was established on October 3, 1958 by the International Council for Scientific Unions (ICSU). Among COSPAR's objectives are the promotion of scientific research in space on an international level, with emphasis on the free exchange of results, information, and opinions, and providing a forum, open to all scientists, for the discussion of problems that may affect space research. These objectives are achieved through the organization of symposia, publication, and other means. COSPAR has created a number of research programmes on different topics, a few in cooperation with other scientific Unions. The long-term project COSPAR international reference atmosphere started in 1960; since then it has produced several editions of the high-atmosphere code CIRA. The code "IRI" of the URSI-COSPAR working group on the International Reference Ionosphere was first edited in 1978 and is yearly updated.
Tor Hagfors was a Norwegian scientist, radio astronomer, radar expert and a pioneer in the studies of the interactions between electromagnetic waves and plasma. In the early 1960s he was one of a handful of pioneering theorists that independently developed a theory that explained the scattering of radio waves by the free electrons in a plasma and applied the result to the ionosphere. He became founding director of the new EISCAT facilities that were then under construction in 1975, by which time he already been director at most of the other incoherent scatter radar facilities in the world. The asteroid 1985 VD1 is named 7279 Hagfors after him.
The IEEE Heinrich Hertz Medal was a science award presented by the IEEE for outstanding achievements in the field of electromagnetic waves. The medal was named in honour of German physicist Heinrich Hertz, and was first proposed in 1986 by IEEE Region 8 (Germany) as a centennial recognition of Hertz's work on electromagnetic radiation theory from 1886 to 1891. The medal was first awarded in 1988, and was presented annually until 2001. It was officially discontinued in November 2009.
James R. Wait was a Canadian electrical engineer and engineering physicist. In 1977, he was elected as a member of National Academy of Engineering in Electronics, Communication & Information Systems Engineering for his contributions to electromagnetic propagation engineering as it affects communication and geophysical exploration.
This is an index to articles about terms used in discussion of radio propagation.
A riometer is an instrument used to quantify the amount of electromagnetic-wave ionospheric absorption in the atmosphere. As the name implies, a riometer measures the "opacity" of the ionosphere to radio noise emanating from cosmic origin. In the absence of any ionospheric absorption, this radio noise, averaged over a sufficiently long period of time, forms a quiet-day curve. Increased ionization in the ionosphere will cause absorption of radio signals, and a departure from the quiet-day curve. The difference between the quiet-day curve and the riometer signal is an indicator of the amount of absorption, and is measured in decibels. Riometers are generally passive radio antenna operating in the VHF radio frequency range (~30-40 MHz). Electromagnetic radiation of that frequency is typically Galactic synchrotron radiation and is absorbed in the Earth's D region of the ionosphere.
Karl Maria Alois Rawer was a German specialist in radio wave propagation and the ionosphere. He developed the analytical code to determine suitable frequency ranges for short wave communication by which German forces built-up their long distance communications during World War II.
William Roy Piggott was a student of Sir Edward Appleton who transferred a large group of German specialists from Austria into the British Zone of Occupation in Germany in 1945. He edited the still valid official booklet of reduction rules for ionospheric soundings with Karl Rawer and was engaged in international activities during the International Geophysical Year (IGY) and for a long time afterwards.
Richard W. Ziolkowski is an American electrical engineer and academician, who was the president of the IEEE Antennas and Propagation Society (2005), and a former vice president of this same society (2004). In 2006, he became an OSA Fellow. He is also an IEEE Fellow. He was born on November 22, 1952, in Warsaw, New York.
Sir William John Granville Beynon, CBE, FRS was a Welsh physicist. He co-operated with Sir Edward Victor Appleton, who had detected the terrestrial Ionosphere.
Levent Gürel is a Turkish scientist and electrical engineer. He was the director of Computational Electromagnetics Research Center (BiLCEM) and a professor in the Department of Electrical and Electronics Engineering at the Bilkent University, Turkey until November 2014. Currently, he is serving as an adjunct professor at the University of Illinois Urbana-Champaign, Department of Electrical and Computer Engineering. He is also serving as the founder and CEO of ABAKUS Computing Technologies.
Radio Science is a quarterly peer-reviewed scientific journal published by Wiley-Blackwell on behalf of the American Geophysical Union and co-sponsored by the International Union of Radio Science. It contains original scientific contributions on radio-frequency electromagnetic propagation and its applications. Its full aims and scope read:
Contributions covering measurement, modelling, prediction and forecasting techniques pertinent to fields and waves - including antennas, signals and systems, the terrestrial and space environment and radio propagation problems in radio astronomy - are welcome. Contributions may address propagation through, interaction with, and remote sensing of structures, geophysical media, plasmas, and materials, as well as the application of radio frequency electromagnetic techniques to remote sensing of the Earth and other bodies in the solar system.
One way of outlining the subject of radio science is listing the topics associated with it by authoritative bodies.
