JET AND THE PROSPECT FOR NUCLEAR FUSION
This paper describes the Joint European Torus (JET) device which was built as a European collaboration effort, with the aim of testing the scientific feasibility of producing controlled thermonuclear reactions between light nuclei with a net yield of energy. JET is the largest magnetic confinement machine in the world both in physical size and in the magnitude of the plasma current (5times106 Amperes). The machine came into operation in mid 1983 and has followed the first stages of a planned evolution, in which the performance is progressively increased mainly by adding more heating power and which will culminate in eventual operation in a deuterium-tritium mixture. This will permit study of the plasma performance when there is a substantial power input from the alpha-particle fusion products. So far operating in deuterium gas with 8 MW of additional heating by neutral beams, a peak ion temperature of 12 keV has been obtained with a corresponding fusion product (density times confinement time) of 8times10"18" m"-3"s. If the same conditions were to be achieved in a deuterium- tritium mixture, then the ratio of thermonuclear power output to the heating power input, Q, would be sim 0.1. It is expected that following further technical improvements to JET, scientific breakthrough'' (namely Q=1) will be achieved. The next step after JET will be to study a burning or ignited plasma in which no power input is required because energy losses are balanced by alpha-particle heating. The requirements for such an experiment will become increasingly clear as more data is obtained from JET. At present it seems likely that a larger apparatus will be needed with a plasma current capability of 12-15 MA. These requirements for the thermonuclear furnace remain broadly consistent with the known technological constraints on an eventual power reactor.
Bibliographic Reference: REPORT JET-P(87)59, 1987, AVAILABILITY: JET, ABINGDON, UK
Record Number: 1989126096800 / Last updated on: 1989-05-01
Available languages: en