The evolution of edge pedestal parameters between edge-localized modes (ELMs) is analyzed for an H-mode DIII-D (Luxon 2002 Nucl. Fusion42 612) discharge. Experimental data are averaged over the same sub-intervals between successive ELMs to develop data that characterize the evolution of density, temperature, rotation velocities, etc over the interval between ELMs. These data are interpreted within the context of the constraints imposed by particle, momentum and energy balance, in particular in terms of the pinch–diffusion relation for radial particle flux that is required by momentum balance. It is found that in the edge pedestal there is an increase in both inward (pinch) electromagnetic and outward (diffusive) pressure gradient forces over the inter-ELM interval.
Dynamical evolution of pedestal parameters in ELMy H-mode in the National Spherical Torus Experiment