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Title	243: 256: SOL width and divertor peak heat flux in QH-mode plasmas with/without n=3 fields
Name:	Andrea Garofalo garofalo@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Inductive Scenarios	Presentation time:	Not requested
Co-Author(s):	K. Burrell, M. Fenstermacher, W. Solomon	ITPA Joint Experiment :	No
Description:	The goal of this experiment is to compare the SOL width and the divertor peak heat flux observed in QH-mode plasmas to the values expected from scalings based on ELMing H-modes. The effect of rotation and the effect of 3D fields will also be investigated.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Using the same tokamak set-up first used on Nov. 1, 2011, we can generate both counter-rotating QH-modes and co-rotating ELMing H-modes, for direct comparisons. By operating soon after a boronization (as on Nov.1) we can maintain the low-density required for QH-mode even with the lower strike point on top of the baffle for documentation with the IR camera.
Background:	QH-mode is an attractive mode of operation for ITER because it enables high confinement without ELMs. Recent experiments have shown that the use of nonresonant magnetic fields (NRMFs) allows QH-mode even with the low co-Ip NBI torque expected in ITER. Furthermore, the energy confinement is higher at lower rotation, unlike in other regimes. Thus, QH-mode provides solution simultaneously to the ELM problem and the usual problems associated with low NBI torque, e.g. low confinement and locked modes. Another major ITER issue is the high peak heat flux expected on the divertor during H-mode operation. The characteristics of the SOL and divertor heat flux for QH-mode plasmas have not been studied yet, mostly because to study the divertor heat flux the strike point needs to be off pumping position, and QH-modes normally require pumping. Experiments on Tuesday Nov. 1, 2011, showed that right after boronization we could get very low density QH-modes without pumping and without the pump-out effect from n=3 fields. This suggests that we should be able to obtain QH-modes in ITER shape with strike point above the lower baffle plate, as long as such experiment is done shortly after boronization.
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