A Predictive Study of the JET Mark II Gas Box Divertor

摘要

1. For given n_s and P_(rad) and vertical targets, the presence or the shape of the septum does not influence appreciably most hydrogenic plasma parameters.rn2. For a recycling impurity introduced to increase radiation, the septum details likewise have little effect on impurity content.rn3. The shape of the septum does affect, however, the content of an intrinsic impurity such as carbon, affecting the approach to detachment and core contamination.rn4. Little difference is found between carbon and nitrogen for fixed P_(rad). However, more C than N is required to radiate the same amount.rn5. There is not enough D flow, resulting from pumping and leakage, for impurity entrainment in the divertor.rn6. The low level of C retention is mainly due to transport and not to the C sputtered from the vessel wall outside the divertor.rn7. Above conclusions hold for both vertical and horizontal targets.rn8. The horizontal target cases have a much higher peak target heat load.rn9. In any case, no solutions have been found with simultaneous detachment, high radiated power fraction and retention of impurities for Mark II GB in JET.