J. B. Taylor – Session III

Taylor:

First, I’d again like to summarize what I hope we said in the last session, and to put it into some sort of chronological order. That interview described my time at Culham, starting in the 1960s. Shortly after joining Culham in 1962 I was appointed head of the Theory Division and joined the Culham management committee. My first important scientific work was a theorem about the Earth’s dynamo. That is still discussed today and appears even in some geophysics textbooks, although it has very little to do with fusion. In fusion, Culham was intended to be the home for a single large reversed field pinch experiment called ICSE, but this experiment was cancelled and the laboratory turned to the study of adiabatic traps and mirror machines. This trend was boosted by my work on the minimum-B and magnetic well configurations, several examples of which were constructed around the world. As far as toroidal plasmas are concerned, an important early contribution with K.V. Roberts was the introduction of quasi-modes. At the time this did not attract much attention but much later it was central to the extensive and important work now known as Ballooning Theory. I also studied the breakup of magnetic surfaces, which is an example of chaos in Hamiltonian systems, where perhaps my main contribution was to introduce the Standard, or Chirikov-Taylor Map. Other work at this time included several studies of adiabatic invariance, much of which was unfortunately unpublished, but it formed the basis for later investigations on micro instabilities. At the end of the 1960s, Culham suffered a major setback when the Lighthill committee recommended a fifty percent reduction in the U.K. work on fusion. Although, in the event the reduction was less drastic than this, it led to a number of long-lasting changes at Culham. One of these was the introduction of “diversification.” This meant that Culham expertise was offered to U.K. industry, and a number of projects were spun off from fusion — such as laser technology, laser machining and the lightning strike testing facility. The effect of this, of course, was that Culham ceased to be purely a plasma physics research institute. Another effect of the cut-back was that, to protect the fusion work, the new director, Bas Pease, made strong and successful efforts to incorporate Culham’s program into the European fusion program under Euratom. (This trend eventually led to Culham’s association with the JET project and, to the sighting of JET at Culham.) That brings us to the 1970s when Culham, like many other fusion labs, turned its attention to the Tokamak Configuration. This followed confirmation by Culham scientists of Russian successes with this device. One of my contributions to Tokamaks, with Bickerton and Connor, was the concept of the Bootstrap Tokamak. At that time, experimenters could find no sign of the Bootstrap Effect, but fifteen years later it was identified by PPL Princeton, and is now a factor in the design of Tokamak reactors, and of ITER. Another contribution at this time, one that I consider to be among my most significant and influential, was the Theory of Plasma Relaxation. This explained some puzzling old observations on ZETA and predicted or interpreted many phenomena on later experiments and has even been applied in the astrophysical area. The second of what I regard as my major contributions was the Ballooning Transformation. This was developed in collaboration with Connor and Hastie. It provides an elegant and powerful method for calculating the stability of short-wave perturbations in toroidal systems and it too is now a standard feature of all Tokamak studies. Coming now on towards the 1980s: the 1980s at Culham were dominated by the design and later the operation of JET. Unfortunately, from the outset I was concerned that the proximity of JET and its political importance would damage Culham’s program by taking resources and staff away from it. This view was not popular with the Culham management and I was eventually excluded from the management committee. Fortunately, I was allowed to continue my own research in the specially created post of chief physicist. This work included further development of the Ballooning Theory, and of Plasma Relaxation, which enjoyed a new lease of life predicting the behavior of new experiments, such as the Spheromak and the Multi Pinch, and leading to a new form of current drive known as Helicity Injection. Together with Jack Connor I introduced the idea of Constrained Scaling Laws, which describes how a plasma parameter, such as temperature, increases with some engineering parameter such as the total current, and connects this relationship with some underlying plasma model. This really completes the account of my career at Culham. In 1989, I left Culham and the U.K. to take up a post as professor of plasma physics at the University of Texas in Austin. There I gave a couple of courses on topics in plasma physics and continued my own research on Plasma Relaxation, Two-Dimensional turbulent plasmas, and a new topic, the damping and structure of drift waves. In 1994, I retired, but have continued research as a consultant to the Theory Division at Culham. Before I conclude I would like to pay tribute to the friends and collaborators who helped me throughout my career. I cannot thank them all, but I would like to acknowledge: My wife Joan, who I married in 1951 when I was in the RAF (and penniless!) and who looked after me, my home, and our children while I was enjoying an exciting career in physics. Keith Roberts, who was my colleague, collaborator and friend from our first meeting in Aldermaston in 1955 and throughout our time together at Culham until his untimely death in 1985. Jack Connor and Jim Hastie who collaborated with me in so much work on fusion that “C H T” became a recognized acronym among fusion theorists. Marshall Rosenbluth, Harold Furth, and Martin Kruskal who accepted me as an equal when they were already leaders in fusion and I was a novice, and later introduced me to many great physicists and helped me to believe that we were engaged in a worthy endeavor. Finally, I’d like to thank Professor Barth for his kindness, and help, and the efficient way in which he’s carried out the interviews.

Barth:

Thank you very much.