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 . Identical profiles of the edge ion temperature Ti were obtained in the experiments with hydrogen and deuterium plasmas while the profile for the H-mode edge pedestal is not fixed but differs by a factor of ∼1.4 (which is the square root of the mass ratio). In addition, an experiment on edge βpol scan was also performed. Higher βpol plasma had higher pedestal Ti value accompanied by greater pedestal width in spite of almost identical at the pedestal. Based on these dimensionless parameter scans, the scaling of the pedestal width was evaluated as .
Advances in understanding the impact of isotope mass on pedestal structure and transport