Sydney Chapman (mathematician)

{{Infobox scientist

| name = Sydney Chapman

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| image = Sydney Chapman.jpg

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| caption = Sydney Chapman 1888–1970

| birth_date = {{Birth date|df=yes|1888|1|29}}

| birth_place = Eccles, Greater Manchester, England

| death_date = {{Death date and age|df=yes|1970|6|16|1888|1|29}}

| death_place = Boulder, Colorado, U.S.

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| workplaces = University of Manchester
University of Cambridge
Imperial College London
University of Oxford
The Queen's College, Oxford
Royal Observatory, Greenwich, University of Colorado

| alma_mater = University of Manchester
University of Cambridge

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| academic_advisors = G. H. Hardy

| doctoral_students = {{Plainlist|

Syun-Ichi Akasofu{{cite journal

| last = Akasofu | first = S.-I.

| date = May 1996

| doi = 10.1029/96ja00182

| issue = A5

| journal = Journal of Geophysical Research: Space Physics

| pages = 10531–10540

| title = Search for the "unknown" quantity in the solar wind: A personal account

| volume = 101}}

Franz Kahn{{cite thesis|last=Kahn|first=Franz Daniel|title=Some problems concerning the luminosity and other properties of the upper atmosphere|date=1950|degree=DPhil|publisher=University of Oxford|url=http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.672862|website=ethos.bl.uk}}
George Frederick James Temple

}}

| notable_students =

| known_for =Chapman cycle
Chapman function
Chapman–Kolmogorov equation
Chapman–Enskog theory

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| awards = {{no wrap|Fellow of the Royal Society (1919){{Cite journal | last1 = Cowling | first1 = T. G.| author-link1 = Thomas Cowling | doi = 10.1098/rsbm.1971.0003 | title = Sydney Chapman 1888–1970 | journal = Biographical Memoirs of Fellows of the Royal Society | volume = 17 | pages = 53–89 | year = 1971 | doi-access = free }}
Smith's Prize (1913)
Adams Prize (1928)
Royal Medal (1934)
Chree Medal and Prize (1941)
De Morgan Medal (1944)
William Bowie Medal (1962)
Copley Medal (1964)}}
Symons Gold Medal (1965)

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}}Sydney Chapman {{Post-nominals|country=GBR|FRS}} (29 January 1888 – 16 June 1970) was a British mathematician and geophysicist.{{Cite journal | last1 = Akasofu | first1 = S. I. | doi = 10.1007/BF00177026 | title = In memoriam Sydney Chapman | journal = Space Science Reviews | volume = 11 | issue = 5 | year = 1970 | page = 599 |bibcode = 1970SSRv...11..599A | s2cid = 120617892 }} His work on the kinetic theory of gases, solar-terrestrial physics, and the Earth's ozone layer has inspired a broad range of research over many decades.{{MathGenealogy|id=122622}}{{Cite journal | last1 = Akasofu | first1 = S. I. | title = The scientific legacy of Sydney Chapman | doi = 10.1029/2011EO340001 | journal = Eos, Transactions American Geophysical Union | volume = 92 | issue = 34 | pages = 281–282 | year = 2011 |bibcode = 2011EOSTr..92..281A | doi-access = free }}{{MacTutor Biography|id=Chapman|title=Sydney Chapman}}[https://web.archive.org/web/20080911232122/http://www.aip.org/history/ead/19990060_content.html Finding aid to papers of Sydney Chapman], Niels Bohr Library and Archives, accessed 7 September 2008[http://www.gi.alaska.edu/chapman/ Sydney Chapman page at the Geophysical Institute of the University of Alaska, Fairbanks] {{webarchive|url=https://web.archive.org/web/20090830021757/http://www.gi.alaska.edu/chapman/ |date=30 August 2009 }} includes sections from Sydney Chapman, Eighty, From His Friends, accessed 4 October 2008

Education and early life

Chapman was born in Eccles, near Salford in England and began his advanced studies at a technical institute, now the University of Salford, in 1902.{{cite book |title=The Biographical Encyclopedia of Astronomers |last=Hockey |first=Thomas |year=2009 |publisher=Springer Publishing |isbn=978-0-387-31022-0 |access-date=22 August 2012 |url=http://www.springerreference.com/docs/html/chapterdbid/58269.html}} In 1904 at age 16, Chapman entered the University of Manchester. He competed for a scholarship to the university offered by his home county, and was the last student selected. Chapman later reflected, "I sometimes wonder what would have happened if I'd hit one place lower." He initially studied engineering in the department headed by Osborne Reynolds. Chapman was taught mathematics by Horace Lamb, the Beyer professor of mathematics, and J. E. Littlewood, who came from Cambridge in Chapman's final year at Manchester. Although he graduated with an engineering degree, Chapman had become so enthusiastic for mathematics that he stayed for one further year to take a mathematics degree. Following Lamb's suggestion, Chapman applied for a scholarship to Trinity College, Cambridge. He was at first awarded only a partial scholarship as a sizar (meaning that he obtained financial support by acting as a servant to other students), but from his second year onwards he received a full scholarship. He graduated as a wrangler in 1910. He began his research in pure mathematics under G. H. Hardy, but later that year was asked by Sir Frank Dyson to be his chief assistant at the Royal Greenwich Observatory.

Career and research

From 1914 to 1919, Chapman returned to Cambridge as a lecturer in mathematics and a fellow of Trinity. He held the Beyer Chair of Applied Mathematics at Manchester from 1919 to 1924, the same position as had been held by Lamb, and then moved to Imperial College London. During the Second World War he was Deputy Scientific Advisor to the Army Council.

In 1946, Chapman was elected to the Sedleian Chair of Natural Philosophy at Oxford, and was appointed fellow of The Queen's College, Oxford. In 1953, on his retirement from Oxford, Chapman took research and teaching opportunities all over the world, including at the University of Alaska and the University of Colorado, but also as far afield as Istanbul, Cairo, Prague, and Tokyo. As the Advisory Scientific Director of the University of Alaska Geophysical Institute from 1951 to 1970, he spent three months of the year in Alaska, usually during winter for research into auroras.{{cite web | author=Keith B. Mather | title=Introduction to Sydney Chapman | url=http://www.gi.alaska.edu/chapman/intro.html | publisher=Geophysical Institute | access-date=20 December 2010 | url-status=dead | archive-url=https://web.archive.org/web/20101207035127/http://www.gi.alaska.edu/chapman/intro.html | archive-date=7 December 2010 | df=dmy-all }} Much of the remainder of the year he spent at the High Altitude Observatory in Boulder, Colorado.Sydney Chapman, eighty: From His Friends

By Sydney Chapman, Syun-Ichi Akasofu, Benson Fogle, Bernhard Haurwitz, University of Alaska (College). Geophysical Institute, National Center for Atmospheric Research (U.S.)

Published by National Center for Atmospheric Research, 1968

Chapman's most noted mathematical accomplishments were in the field of stochastic processes (random processes), especially Markov processes. In his study of Markovian stochastic processes and their generalizations, Chapman and the Russian Andrey Kolmogorov independently developed the pivotal set of equations in the field, the Chapman–Kolmogorov equations. Chapman is credited with working out, in 1930, the photochemical mechanisms that give rise to the ozone layer.

Chapman is recognised as one of the pioneers of solar-terrestrial physics. This interest stemmed from his early work on the kinetic theory of gases. Chapman studied magnetic storms and aurorae, developing theories to explain their relation to the interaction of the Earth's magnetic field with the solar wind. He disputed and ridiculed the work of Kristian Birkeland and Hannes Alfvén, later adopting Birkeland's theories as his own.Lucy Jago (2001). The Northern Lights. New York: Alfred A. Knopf. {{isbn|0-375-40980-7}}{{Cite journal | last1 = Schuster | first1 = A. | title = The Origin of Magnetic Storms | doi = 10.1098/rspa.1911.0019 | journal = Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | volume = 85 | issue = 575 | pages = 44–50 | year = 1911 |bibcode = 1911RSPSA..85...44S | doi-access = free }} Chapman and his first graduate student, V. C. A. Ferraro, predicted the presence of the magnetosphere in the early 1930s. They also predicted characteristics of the magnetosphere that were confirmed 30 years later by the Explorer 12 satellite.

In 1940, Chapman and a German colleague Julius Bartels published a book in two volumes{{cite book|title=Geomagnetism, Vol. I, Geomagnetic and Related Phenomena|year=1940|publisher=Oxford Univ. Press|author=Sydney Chapman|author2=J. Bartels }}{{cite book|title=Geomagnetism, Vol. II, Analysis and Physical Interpretation of the Phenomena|year=1940|publisher=Oxford Univ. Press|author=Sydney Chapman|author2=J. Bartels }} on geomagnetism, which was to become the standard text book for the next two decades. In 1946 Chapman coined the term: Aeronomy, which is used today to describe the scientific field of high-altitude research into atmosphere/space interaction.Sydney Chapman, "Some Thoughts on Nomenclature," Nature 157, (1946): 405. Available on-line at: [http://www.nature.com/nature/journal/v157/n3987/abs/157405b0.html Nature].

From 1951 to 1954, Chapman was president of the International Union of Geodesy and Geophysics (IUGG).

Chapman was President of the Special Committee for the International Geophysical Year (IGY). The idea of the IGY stemmed from a discussion in 1950 between Chapman and scientists including James Van Allen. The IGY was held in 1957–58, and resulted in great progress in fields including Earth and space sciences, as well as leading to the first satellite launches.{{cite web|archive-url=https://web.archive.org/web/20160702101001/http://www.nas.edu/history/igy/|archive-date=2016-07-02|url=http://www.nas.edu/history/igy/|url-status=dead|publisher=National Academy of Sciences|title=The International Geophysical Year}}

= Honours and awards =

Chapman was bestowed many honours over his career, including Smith's Prize in 1913, election as a Fellow of the Royal Society in 1919, Invited Speaker of the ICM in 1924,{{cite book|author=Chapman, S.|author2=Whitehead, T. T.|chapter=The influence of electromagnetic induction within the earth upon terrestrial magnetic storms|title=In: Proceedings of the International Congress of Mathematicians in Toronto, August 11–16. 1924|volume=2|pages=313–338|chapter-url=http://www.mathunion.org/ICM/ICM1924.2/Main/icm1924.2.0313.0338.ocr.pdf|url-status=dead|archive-url=https://web.archive.org/web/20171201043915/http://www.mathunion.org/ICM/ICM1924.2/Main/icm1924.2.0313.0338.ocr.pdf|archive-date=1 December 2017}} Royal Society Bakerian lecturer in 1931, Royal Society Royal Medal in 1934, London Mathematical Society De Morgan Medal in 1944. In 1949, he was awarded the Gold Medal of the Royal Astronomical Society and was elected as a Fellow of the Royal Society of Edinburgh in 1953. In 1964, he was awarded the Copley Medal of the Royal Society and in 1965 the Symons Gold Medal of the Royal Meteorological Society. He was elected to the National Academies of Science of the United States, Norway, Sweden and Finland. He served as president of the London Mathematical Society during 1929–1931 and the Royal Meteorological Society 1932–1933.

The lunar Crater Chapman is named in his honour, as is the Sydney Chapman Building on the campus of the University of Alaska Fairbanks. This building served as the first permanent home of the University of Alaska Geophysical Institute, and it now contains the Department of Computer Science and the Department of Mathematics and Statistics.{{cite web|author=Kieth B. Mather|year=1970|title=Sydney Chapman (obit)|website=University of Alaska|url=http://www.alaska.edu/uajourney/notable-people/fairbanks/sydney-chapman}} The American Geophysical Union organises "Chapman Conferences," which are small, topical meetings intended to foster innovative research in key areas.{{cite web|title=Chapman Conferences |url=http://www.agu.org/meetings/chapman/ |access-date=28 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110805184434/http://www.agu.org/meetings/chapman/ |archive-date=5 August 2011 }} The Royal Astronomical Society founded the Chapman Medal in his memory.{{cite book|last1=Tayler|first1=R.J.|title=History of the Royal Astronomical Society: Volume 2 1920–1980|date=1987|publisher=Blackwell|location=Oxford|isbn=0-632-01792-9|page=202}}