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Title	375: QH-mode pedestal optimization
Name:	Philip Snyder snyderpb@ornl.gov	Affiliation:	Oak Ridge National Lab
Research Area:	Inductive Scenarios	Presentation time:	Not requested
Co-Author(s):	K. Burrell, T. Osborne, R. Groebner	ITPA Joint Experiment :	No
Description:	Previous theory-motivated optimization of the pedestal in QH mode via improvements in shape and increasing density have enabled high pedestal pressure and high performance in QH mode. The EPED model predicts that further optimization, including possible access to "Super H-Mode" should be possible, and enable substantial performance improvements. An important tool that has not been employed is the controlled puffing of low-Z impurities (eg Ne or N) to enable control of Zeff at a given density. The EPED model predicts that this should increase pedestal pressure and possibly enable QH-mode access. It also is predicted to be an avenue for obtaining high performance in ITER without exceeding the Greenwald limit.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Conduct a detailed optimization study beforehand with the EPED model to determine optimal shape and range of density and Zeff. In a very strongly shaped, but single null, configuration with good wall conditions, obtain QH mode. Ramp down rotation with time to produce a density scan in each discharge. Increase impurity puff rate to vary Zeff across a series of shots. Select optimal conditions for detailed diagnosis and performance extension.
Background:
Resource Requirements:	1+ days
Diagnostic Requirements:	pedestal structure and turbulence diagnostics.
Analysis Requirements:	EPED runs before the expt
Other Requirements: