DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
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Title	372: Pedestal optimization via impurity injection
Name:	Philip Snyder snyderpb@ornl.gov	Affiliation:	Oak Ridge National Lab
Research Area:	Pedestal Structure	Presentation time:	Not requested
Co-Author(s):	T. Osborne, R. Groebner	ITPA Joint Experiment :	No
Description:	The EPED model predicts that, in strongly shaped plasmas, the pedestal height depends strongly on collisionality, and can be optimized dynamically by starting at low collisionality, and slowly increasing collisionality with time. In addition to density variation, it is possible to modify the pedestal collisionality by injecting low-Z impurities to increase Zeff. Here we propose to control edge collisionality by injection of Neon or Nitrogen, to study the physics of this effect, and to optimize the pedestal pressure to allow high performance at a range of densities.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	In a very strongly shaped plasma, scan density and Zeff via impurity injection (Ne or N). Make predictions with EPED ahead of time to guide choice of shape, Ip, Bt and optimal range of Zeff and density. Experiment could be conducted either in ELMing or QH mode discharges.
Background:
Resource Requirements:	Ne or N injection at substantial gas rates. Core pellet fuelling also desirable
Diagnostic Requirements:	Pedestal profile and turbulence diagnostics
Analysis Requirements:	EPED studies ahead of experiment
Other Requirements: