Wilhelm Altar


Wilhelm Altar
Vienna, Austria
Death date
Associated organizations
Princeton University
Fields of study


Wilhelm Altar was an Austrian physicist who contributed to the development of magneto-ionic theory.

Altar was born in Vienna in 1900 and obtained a doctorate in theoretical physics from the University of Vienna in 1923. He also studied engineering at the Technische Hochschule in Vienna. Unable to obtain a professorship in theoretical physics, he worked as a part-time researcher at a radio laboratory. Following a meeting with the noted British physicist A.O. Rankine, he decided to move to his uncle’s home in London in 1925. On Rankine’s advice, Altar began working with Edward Appleton at King’s College in London.

Appleton and his colleagues were mapping the outlines of magneto-ionic theory. Altar took on the task of studying wave propagation. According to historian C. Stewart Gillmor, Altar’s 1925 manuscript, “Wave Propagation in Ionized Gases under the Influence of a Magnetic Field,” was a major source for Appleton’s Nobel Prize-winning work describing how radio waves operated in the atmosphere. Altar’s work “presented for the first time the magneto-ionic plasma dispersion relation,” wrote Gillmor in a 1982 article, and contained “the equations for polarization and complex refractive index.” Appleton and Altar planned to write a joint article describing these findings, but Altar had to return to Vienna in 1926 for financial reasons. Altar's contribution to Appleton's research remained uncredited for decades.

Altar moved to the United States in the early 1930s and joined the physics department of Pennsylvania State University. He served as a researcher at the Frick Chemical Laboratory at Princeton University from 1935 to 1937, working on a study of optical rotatory power in organic molecules. In addition to teaching at several other universities and working on radar experiments during World War II, he performed research on microwaves and information theory at Westinghouse Research Laboratories in the 1940s and 1950s. He subsequently worked in the aerospace industry, at companies that included Douglas Aircraft and the Aerospace Corporation. He was a lieutenant colonel at the Naval Research Laboratory upon his retirement in 1972. He died in 1995.

Further Reading

Wilhelm Altar, Edward Appleton, and the Magneto-Ionic Theory, C. Stewart Gillmor, Proceedings of the American Philosophical Society, Vol. 126, No. 5 (Oct. 21, 1982), pp. 395-440