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	159: Collisionality dependence of pedestal height with RMP
Name:	Raffi Nazikian nazikian@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Pedestal Structure	Presentation time:	Requested
Co-Author(s):	Todd Evans, Tom Osborne, ...	ITPA Joint Experiment :	No
Description:	RMPs are known to suppress ELMs but at the cost of plasma performance at low collisionality. However on ASDEX-U ELM suppression is observed without significant impact on performance. This proposal aims to understand the role of collisionality and edge density on the edge pedestal pressure in ELMing discharges. They key question is whether the effect of density pump out on the pedestal height is consistent with P-B theory and experiment in plasmas where q-95 is outside of the ELM suppression window. The implication, if true, is that we can better predict the impact of the RMP on the pedestal height in ITER with the application of RMPs if the physics that determines the pedestal height with RMP in typical ELMing discharges is determined entirely by P-B theory and KBM physics. Basically, confirming the EPED1 model vs collisionality for RMP plasmas would help establish a predictive understanding of how RMPs may affect the pedestal height and width in ITER, leading to more reliable predictive understanding of RMP physics.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Use the ITER baseline scenario. Repeat the experiment performed by Tom Osborne that showed the pedestal scaling with collisionality by adding RMP even parity and avoiding q-95 resonant window for ELM suppression. Use additional ECH and gas puff where needed to affect edge collisionality. Shift strike point or turn off cryo pump to further affect collisionality and edge density with RMP. Compile data that cam be compared with collisionality scans in the absence or RMP. Use this to extrapolate to pedestal performance in ITER with RMP.
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