The JET results and the scientific feasibility of thermonuclear fusion

JET has successfully achieved and contained plasmas of thermonuclear grade. Individually, parameters required for a fusion reactor have been achieved, and simultaneously, the fusion product ni τETi is less than a factor of 10 from ignition. Consequently the problems of heating and confining a thermonuclear plasma may be regarded as solved. They also make possible the definition of the size and current of an experimental reactor. Control of impurities, fuelling and exhaust of helium are essential to produce and maintain an ignited plasma. It is proposed to address these problems in JET. By 1994, an axisymmetric pumped divertor should have demonstrated that impurity control of thermonuclear grade plasmas is possible. This should also improve the JET plasma performance and raise the total fusion power to the level of the additional heating power