James Wynne Dungey (1923–2015) was a British space scientist who was pivotal in establishing the field of space weather and made significant contributions to the fundamental understanding of plasma physics.
Early life and education Dungey grew up in Stamford, Lincolnshire, the son of a schoolteacher. During World War II, he worked at British Thompson-Houston in Rugby, on developments for radar. After the end of the war, he gained a degree in 1947 from Magdalene College, Cambridge, part of the University of Cambridge. He then completed a Ph.D. at the same institution, under the supervision of Fred Hoyle.
Career and research From 1950 to 1953 Dungey worked at the University of Sydney with Ron Giovanelli, from 1953 to 1954 at Pennsylvania State University, and from 1954 to 1957 back at the University of Cambridge. From 1957 to 1959 he was a mathematics lecturer at King's College, Newcastle upon Tyne (now Newcastle University) and from 1959 to 1963 he worked at the UK Atomic Weapons Establishment. In 1963 he moved to the Blackett Laboratory of Imperial College London, where he was a physics professor from 1965 to until his retirement in 1984.
The discovery of magnetic reconnection Dungey introduced the concept of magnetic reconnection, a mechanism that was not initially accepted but is now recognized to be of fundamental importance in all areas of plasma (ionized gas) physics. Magnetic reconnection has key effects on astrophysical, space, and laboratory plasmas in converting magnetic energy into heat and energised charged particles. It also enables a wide range of phenomena by reconfiguring magnetic field lines. Reconnection is a process that occurs in the solar corona, interplanetary space, Earth's magnetosphere, fusion tokamaks and many astrophysical objects. It is also the key controlling factor in space weather effects on operational systems, causing the release of energy in solar flares and coronal mass ejections (CMEs) and being the key mechanism that transfers energy from the solar wind flow (and its enhancement due to CMEs) to Earth's space environment, the magnetosphere. It is also very important in fusion research, causing problems for the magnetic confinement of the plasma in tokamaks but is harnessed in some devices to help compress the plasma. Dungey considered the origins of the known system of currents in the polar ionospheres detected using high-latitude magnetometers. He had been steered toward this work by his PhD supervisor, Fred Hoyle, after Hoyle examined the DSc thesis of Ron Giovanelli in Sydney, Australia—a thesis that contained the concept of magnetic nulls acting to power solar flares by annihilating oppositely-directed magnetic fields at current sheets. Hoyle wondered if some such mechanism could power Earth's aurora. Dungey's innovations were to restrict the region of magnetic interaction in the current sheet and predict the magnetic field topology changes: this allowed energised particles and reconnected magnetic flux to escape along the current sheet
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