Appleton, Edward Victor

Born Sept. 6, 1892, in Bradford, Yorkshire; died Apr. 21, 1965, in Edinburgh. British physicist. Fellow of the Royal Society of London (1927).

Appleton graduated from Cambridge University in 1914. He was a professor at the University of London from 1924 to 1936 and at Cambridge University from 1936 to 1939. From 1939 to 1949, he was the permanent secretary of Great Britain’s Department of Scientific and Industrial Research. In 1949 he was appointed principal and vice-chancellor of the University of Edinburgh.

Appleton’s main works dealt with radio physics and geophysics. In 1924, simultaneously with the American physicist S. Barnett, Appleton discovered experimentally a conducting layer of the ionosphere that reflects radio waves and whose existence had been predicted earlier by A. E. Kennelly and O. Heaviside; the layer is now known as the E layer, or Heaviside layer. In 1927, Appleton discovered a second, higher reflecting layer, which was first named the Appleton layer but later called the F₁ and F₂ layers; the F₂ layer is now also referred to as the Appleton layer.

Appleton showed that radio waves reflected by the Heaviside and Appleton layers are elliptically polarized; he calculated the reflection coefficient and electron density in the layers. He developed a theory of ionospheric dispersion and birefringence and showed that both auroras and the conductivity of the upper layers of the ionosphere are associated with solar activity. He also wrote works on radar.

In 1947, Appleton received a Nobel Prize for his work in the study of the ionosphere.