Growth of the edge pedestal in JT-60U ELMy H-mode

In JT-60U ELMy H-mode plasmas, the width of the edge pedestal Delta(ped) ob served in the ion temperature profiles is two to three times larger than th at in the edge localized modes (ELM)-free plasmas. At high triangularity, D elta(ped) reaches 8-15 cm (9-16% of the minor radius) at the plasma current of 1 MA. In the high triangularity ELMy H-mode, the ion temperature at the pedestal shoulder and Delta(ped) can increase gradually with a time consta nt of similar to 2-3 s, which is longer than the global energy confinement time by one order of magnitude. In addition, pressure gradient in the pedes tal layer increases simultaneously. The width Delta(ped) scales linearly wi th the poloidal gyro radius of thermal ions rho(pi) at a fixed peripheral s afety factor q(95) (Delta(ped) similar to 3-4 rho(pi) at q(95) = 3-4). and has a weak dependence on q(95); Delta(ped) similar to 5 rho(pi)q(95)(-0.3). The shrinkage of Delta(ped) observed at a high density can be explained by a decrease in the edge ion temperature with respect to a decrease in rho(p i). At a higher q(95)(similar to 6) a further increase in Delta(ped) was ob served after the disappearance of ELMs.