Whittaker Colloquium, Oct 2nd 2017, Prof. Keith Moffatt, Cambridge.
From Lyubov Chumakova on October 13th, 2017
Image: Prof. Keith Moffatt (left), Sir Edmund T. Whittaker (bust in bronze by Benno Schotz, RSA, made at the request of the Society and acquired by subscription of Fellows 1945) (center), Sir Michael Atiyah (right) at the Royal Society of Edinburgh https://www.rse.org.uk/.
To download the presentation slides please click http://www.maths.ed.ac.uk/~aar/moffattslides.pdf .
Professor Keith Moffatt (Cambridge) https://sites.google.com/site/hkeithmoffatt/
gave a Whittaker Colloquium at the School of Mathematics, University of Edinburgh with the introduced by Sir Michael Atiyah.
Topological Fluid Dynamics
Since the time of Helmholtz, Tait, Maxwell and Kelvin, the fact that vortex tubes can in principle be knotted and/or linked has excited much interest and speculation. Only quite recently however have knotted and linked vortices been experimentally generated. Such vortices are generally chiral in character, the simplest measure of this chirality being their helicity, an invariant of the Euler equations governing ideal fluid flow. A natural bridge between fluid mechanics and topology is provided by the fact that the normalised helicity of a closed vortex tube is the sum of ‘writhe plus twist’, a known topological invariant of a knotted ribbon.
Helicity is of central importance in the dynamo theory that seeks to explain the observed existence of magnetic fields in planets, stars and galaxies. It is now well established that if, in a turbulent conducting fluid of sufficient extent, the mean helicity is nonzero, then the medium is unstable to exponential growth of a large-scale magnetic field. This growth is arrested only when the Lorentz force distribution is strong enough to control the flow, whatever the ultimate source of energy may be. This theory will be presented, and some important remaining challenges described.
The Whittaker Colloquium is a yearly lecture in the honour of Sir Edmund Taylor Whittaker (1873-1956) held at the School of Mathematics of the University of Edinburgh.
Previous Whittaker Colloquium speakers include: Sir Roger Penrose, Andrew Blake, Edward Witten, Alain Connes, Janos Pintz, Endre Szemerédi, John Stillwell, Gunnar Carlsson, Robbert Dijkgraaf, Peter Kronheimer, Philip Maini, Richard Melrose, Terence Tao and Sir Christopher Zeeman.
Sir Edmund Taylor Whittaker (1873-1956)
Whittaker has been described as "one of the great mathematical scholars and teachers of the century."  He was born at Southport and educated at Manchester Grammar School and Trinity College, Cambridge, where he was Second Wrangler in 1895. He was elected a Fellow of Trinity in 1896 where he produced the first edition of his books Modern Analysis (1902) and Analytical Dynamics (1904). In 1906 he became Royal Astronomer of Ireland and Professor of Astronomy in the University of Dublin where his History of the Theories of Aether and Electricity ... was published in 1910. In 1951 he revised and amplified this work and, in his eightieth year, published a second volume which brought the history up to 1926. In 1912 he was appointed to the Chair of Mathematics at the University of Edinburgh from which he retired in 1946. Here he founded a school of research and a mathematical laboratory which led to the publication of The Calculus of Observations with G. Robinson. His later concern was the reconciliation of science and cosmogony with revealed religion.
Elected to the Fellowship in 1912, he served on Council in various capacities for 22 years and as President from 1939 to 1943.
Council appointed a small committee in 1944 "to look into the
question of a portrait or bust of Professor E T Whittaker, FRS, lately
President of the Society". Mr Stanley Cursiter, RSA, was a member of this
committee and guided it in its choice of sculptor and in the design of the
pedestal and plate. Two bronze heads were prepared, one for the Society and the
other was presented to Sir Edmund. The head was exhibited at the
Exhibition of the Royal Scottish Academy in 1946. 
For more information on Whittaker, please see:
1 Edinburgh University Journal 1955-57, p.126.
2 RSE Council Minutes of 4th December 1944; 8th January, 5th February, 7th May, 4th June, 2nd July 1945; 14th January, 6th May 1946; and 3rd May 1948 refer.
3 The Royal Scottish Academy Exhibitions 1826–1990. Ed. Charles Baile de Laperriere, 4 vols. Hilmartan Manus Press 1991, note 2.