The improved divertor confinement (IDC) phenomenon, observed in the JT-60 tokamak, is explained using collisional transport theory. The model successfully describes the correlation between the increase in radiated power at the divertor and the increase in line averaged density of the plasma, which is characteristic of the IDC. Other prominent features of IDC, such as the grad-B drift dependence, divertor heat flux asymmetries and carbon-oxygen impurity exchange, are also explained. The model predicts that IDC could be obtained in deuterium plasmas. The reduction in heat load to the divertor caused by IDC would be an important benefit for a fusion reactor.
Divertor and edge plasma properties in doublet III expanded boundary discharges