"Controlled Thermonuclear Research in the United Kingdom" - P.C. Thonemann


" The British thermonuclear scientists do not say flatly that they are ahead of their U.S. colleagues, but Dr. Thonemann, master of ZETA, points out that with a small thermonuclear doughnut it is hard to keep the pinch away from the walls for long. "You have to go fairly big," he says, "if you want to put up temperature and put up containment time too." The U.S. Atomic Energy Commission apparently agrees with this reasoning; it is building at Princeton, N.J. a very large thermonuclear device, a "Stellarator," which is scheduled to start operation in 1960. "

'Master of ZETA' P.C. Thonemann in an article with TIME Magazine in Feb 1958.

" Discouragement with the pinch did not appear to discourage the British, whose ZETA and SCEPTRE devices are based on pinch, They listened to all counter arguments. Asked why they stuck to the pinch and whether they thought a multiple approach might be better, they replied that a limited effort should be directed where it appears to have the greatest possibilities. Pinch, they repeated, appears to them to have the greatest possibilities. To a NUCLEONICS question as to whether political pressure at home might force diversification, they replied that they felt that they might be required to at least try some of the other approaches. "

From "Fusion: Where do we stand?", NUCLEONICS Magazine September 1958. By the end of 1958 ZETA was shut down.

Metal torus (1949) used by Thonemann and Cowhig to study the "pinch effect" produced by 100 kilocycle continuous excitation. (The iron core which linked the torus is not shown)

P.C. Thonemann

P.C. Thonemann was Head of the Nuclear Fusion programme at Harwell, England. He was working in the fields of nuclear fusion and plasma physics. His contribution to the conference, "Controlled Thermonuclear Research in the United Kingdom" was giving an insight into the United Kingdom's programme.



"I now turn to the future of research in the controlled fusion field. To my mind, the problem of stability is of paramount importance. Unless the rate at which charged particles cross magnetic lines of force can be reduced to that given by classical diffusion theory, the loss of energy to the walls will prevent fusion reactions from becoming a practical power source. A decrease in the energy flux to the walls byparticle bombardment also reduces the amount of impurities thrown into the plasma and this in turn reduces the energy loss by radiation. Assuming that the stability problem is solved, it is estimated that currents of about 10 million amperes will be required in a tritium-deuterium mixture before a net balance of power is achieved using self-magnetic confinement. In a tube of reasonable dimensions, these currents must continue for at least one-tenth of a second. Achieving such current amplitudes clearly presents difficult technological problems. I think that the papers to be presented at this Conference, and the discussions which follow them, will show that it is still impossible to answer the question, 'Can electrical power be generated using the light elements as fuel by themselves?' I believe that this question will be answered in the next decade. If the answer is yes, a further ten years will be required to answer the next question, 'Is such a power source economically valuable?' "



View his paper: "Controlled Thermonuclear Research in the United Kingdom"














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