Progress in characterization of the H-mode pedestal

The H-mode pedestal remains a critical subject for magnetic fusion energy research. Recent experimental efforts to characterize the edge pedestal, for tests of pedestal models now under development, are summarized in this report. The pedestal transport is characterized by the profiles and energy and particle fluxes through both the electron and ion channels. The flux measurements are made difficult by the short scale lengths of the pedestal and the difficulty of measuring the neutral ionization source within the pedestal. Recent results on pedestal scaling with a number of parameters are also summarized. Measurements of the pedestal scaling with the ion gyroradius, global beta, input power, shape, critical gradients, neutral density, aspect ratio, rotation, toroidal ripple and the toroidal field direction are presented. These measurements provide a strong test for emerging pedestal models as well as improve confidence of extrapolating existing experiments towards future devices. Recent work on the scaling of the H-mode power threshold is also presented.

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