Recent results on the understanding and scaling of several of the operationalboundaries found in ELMy H-mode plasmas are presented. Divertor geometry isfound to be important in determining the H-mode transition power andtemperature. Recent experiments from different tokamaks find apparentlyconflicting evidence for the role of the edge neutral density in controllingthe H-mode transition and further intermachine comparisons are clearlywarranted. Significant progress has been made both on the understanding andon the avoiding of the H-mode density limit. Models based on divertordetachment andon MARFE physics reproduce the empirical density limit scalings. The densitylimit in ELMy H-modes has been increased by changing the profile of thedensity in the divertor and in the main plasma. Highly radiating ELMy H-modesare currently being studied and display some of the favourable characteristicsof the TEXTOR radiative improved confinement mode.
Progress in quantifying the edge physics of the H mode regime in DIII-D