Studies in JET divertors of varied geometry II: Impurity seeded plasmas
In current large tokamaks non-intrinsic seeded impurities have been used to produce divertor power loads which would be considered acceptable when extrapolated to the international thermonuclear experimental reactor (ITER). Many devices have achieved the goal of high fractional radiated powers, small frequent edge-localized modes (ELM) and detachment which are characteristic of radiative H-mode regimes. However, it has been a matter of concern that the Z(eff) associated with the seeded impurities may exceed that allowable in ITER and also that the degradation in energy confinement may be unacceptable. Confidence can only be built in the prediction of these parameters in ITER if reliable scalings are available for impurity content and energy confinement which have a sound physics basis. This paper describes work at the Joint European Torus (JET) in this area whilst using multi-machine data to characterize the size scaling and provide a context for the JET data. Predicted levels for the impurity content of seeded ITER plasmas appear to be of marginal acceptability. The situation with regard to confinement is less clear.
Bibliographic Reference: Report: JET-P(98)20 EN (1998) 30pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199811098 / Last updated on: 1998-09-28
Original language: en
Available languages: en