Nigel Oscar Weiss

Astrophysicist and applied mathematician Nigel Oscar Weiss, who made many fundamental contributions to our understanding of magnetohydrodynamics (MHD) the Sun’s magnetic field, died on 24 June 2020 in Cambridge, UK. Weiss JOHN H. THOMASPPT|High-resolutionNigel was born 16 December 1936 Johannesburg, South Africa. He educated at Hilton College Natal (which he hated) then Rugby School UK loved). studied natural sciences Clare College, Cambridge University. His graduate work supervised by geophysicist Edward Bullard. began with fieldwork seismology but soon switched theoretical MHD. dissertation examined variable hydromagnetic motions.After receiving his PhD, joined newly opened Culham Laboratory Oxfordshire. There wrote classic paper showing that combined effects advection diffusion an array cellular eddies expel flux from eddies’ cores produce a concentrated field along their boundaries. That groundbreaking involved development stable numerical discretization schemes, which used extensively later research.In 1965 returned as lecturer department mathematics physics (DAMTP). One us (Thomas) postdoctoral fellow DAMTP 1966–67 benefited Nigel’s sage advice methods for solving MHD equations. remained rest career, becoming reader 1979, professor mathematical astrophysics 1987, emeritus retirement.A problem continued interest throughout career magnetoconvection—that is, thermal convection electrically conducting fluid presence field. students collaborators advanced knowledge magnetoconvection new ideas, some derived active subject chaos theory, simulations increasing sophistication. They added nonlinear compressibility, led applications near-surface culminated 2014 monograph Magnetoconvection, one (Proctor) coauthor. great progress complex dynamical interaction between strong intermittent fields organized into “flux tubes” surrounding convection.Nigel particularly interested sunspots, are perhaps best “laboratory” observing magnetohydrodynamic behavior under astrophysical conditions. 1970s Friedrich Meyer, Hermann Schmidt, Peter Wilson influence formation decay sunspot. For (Thomas), sunspots were several collaborations Nigel: We NATO workshop them, review articles, published monograph, Sunspots Starspots (2008). With Nicholas Brummell Steven Tobias, we showed pumping solar granulation can explain features sunspot structure evolution. Although theoretician heart, kept close touch observations, often through visits Sacramento Peak Observatory interactions Alan Title group Lockheed, observations space.Nigel also contributed significantly dynamo study way motions sustain Using low-order models, first explore chaotic dynamos, related 22-year cycle, especially concerning occurrence Maunder minimum (from 1645 1715) other periods reduced activity. Jürg Beer investigated historical record cycle modulations—with radioisotope variations tree rings ice data—and those irregularly modulated cycles could be interpreted theoretically models. wife, Judy, scholar English Robinson poem Andrew Marvell contains earliest references disappearance late 17th century.Nigel participant academic social life college, Clare, served university chair its Physical Sciences 1993 1998. president Royal Astronomical Society 2002 awarded Gold Medal 2007 research astrophysics.A man exceptionally broad interests, read traveled widely, loved music, collected modern art, scientific advisory board UK’s National Gallery. Judy established educational trust Cape Town, Africa, support underprivileged backgrounds. kind mentor colleagues, exuded quiet authority, modest about own achievements.© 2021 American Institute Physics.