Dimensionless parameter dependence of H-mode pedestal width using hydrogen and deuterium plasmas in JT-60U

The characteristics of the spatial width of the H-mode pedestal were investigated in hydrogen and deuterium plasmas in JT-60U. Both the database analysis and the dedicated experiments on the mass scan indicated that the pedestal width depends very weakly on the plasma particle species or rho(pol)*(proportional to m(0.5)). Identical profiles of the edge ion temperature T(i) were obtained in the experiments with hydrogen and deuterium plasmas while the rho(pol)* profile for the H-mode edge pedestal is not fixed but differs by a factor of similar to 1.4 (which is the square root of the mass ratio). In addition, an experiment on edge beta(pol) scan was also performed. Higher beta(pol) plasma had higher pedestal T(i) value accompanied by greater pedestal width in spite of almost identical rho(pol)* at the pedestal. Based on these dimensionless parameter scans, the scaling of the pedestal width was evaluated as Delta(ped) proportional to a rho(*0.2)(pol)beta(pol0.5).