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Sir Edmund Whittaker Memorial Prize

In 1979, Mitchell A. Berger graduated B.A. Magna Cum Laude from Princeton University, majoring in Physics. By 1984 he had obtained an M.A. and Ph.D. in Astronomy from Harvard. After two years as a research fellow at the National Center for Atmospheric Research in Boulder, Colorado, he moved in 1986 to St. Andrews University, where he held a Postdoctoral Fellowship in the Department of Mathematical Sciences, working with Professor E. R. Priest in the Solar Theory research group. In 1989, he was appointed lecturer in the Department of Mathematics of University College London, where he was recently promoted to a readership. Mitchell Berger's research encompasses astrophysics and space physics, fluid dynamics, probability theory and knot theory: indeed, he has touched every one of the areas, pure and applied mathematics, mathematical physics and statistics, for which the Whittaker Prize can be awarded! Most of his work has concerned topological fluid dynamics and magneto-fluid dynamics, with the aim of better understanding turbulent flows. This led him to discover new invariants for braids (i.e. entangled strings with fixed endpoints), applicable not only to tangled vortex or magnetic field lines in fluids but also to long polymer filaments. His work in Solar Physics has involved examination of experimental data from the Solar Maximum Mission satellite and development of theoretical models of aspects of solar flares and coronal heating. But he has not focussed narrowly on one area of application, and has collaborated fruitfully with pure mathematicians (including a Fields Medal winner) on the theory of knots and braids. He has himself written, with characteristic modesty, that "I attempt to master the rather distinct languages of astronomers, physicists, applied mathematicians and pure mathematicians, so that I may assist in encouraging communication between these groups". The award of the Whittaker Prize is recognition of his success.