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	224: Determination of minimum confinement degradation for ELM suppression with I coils
Name:	Alberto Loarte-Prieto Alberto.Loarte@iter.org	Affiliation:	ITER Organization
Research Area:	ELM Control	Presentation time:	Requested
Co-Author(s):	T. Evans, O. Schmitz, G. Huijsmans	ITPA Joint Experiment :	No
Description:	To determine which is the minimum pedestal pressure drop required for ELM suppression with I-coils and the associated confinement degradation and its dependence on plasma shape, input power, coil current spectrum (n=2,3) and their detailed temporal shape when accessing the H-mode.	ITER IO Urgent Research Task :	Yes
Experimental Approach/Plan:	To establish the minimum level of current in the I coils to get ELM suppression in a high delta with optimum q95 ~3.5, n=3 and a pre-I coil betaN_1.8 and the two absolute phases of the perturbation with respect to the known error field in DIII-D. Document the pressure decrease at ELM suppression and the associated plasma energy decrease. Optimize the waveform of I(t) and P_NBI(t) to access ELM suppression with minimum confinement degradation. Repeat at higher beta (beta_N = 2.2). Repeat the experiment with n=2. If feasible attempt the same experiment with a low delta configuration
Background:	ELM suppression can cause a decrease of the pedestal pressure and overall plasma energy but the level of decrease depends on plasma configuration, on the level of current in the I-coils, on the absolute phase of the perturbation and on the temporal waveform of the I coil and input power when accessing the H-mode and the ELM suppressed regime in ways that are not properly quantified nor understood.
Resource Requirements:	NBI injection, I coils in n=3 and n=2 configuration
Diagnostic Requirements:	Core and pedestal plasma diagnostics to document plasma parameter and confinement changes. MHD measurements to determine mode activity.
Analysis Requirements:	Edge stability analysis
Other Requirements: