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	167: Control of radiation asymmetries by application of external field on SPI/MGI shutdown
Name:	Nicolas Commaux commaux@fusion.gat.com	Affiliation:	Oak Ridge National Lab
Research Area:	Disruption Mitigation	Presentation time:	Not requested
Co-Author(s):	V. Izzo, L. Baylor, E. Hollmann, D. Humphreys, P. Parks, N. Eidietis, J. Wesley	ITPA Joint Experiment :	No
Description:	Determine the role of the n=1 mode during the shutdown in the magnitude of the radiation assymetries. This is done by applying an external n=1 field during the shutdown process with MGI/SPI in order to change the behavior (lock ?) the n=1 mode responsible (according to NIMROD simulations) for the bulk of the radiation assymetries observed during a massive particle injection. Using the new IR periscope and scanning different phases of the n=1 could show that the IR footprint of the thermal quench evolves due to the n=1 seed. That would be a proof that the MHD activity is responsible for the asymmetry.	ITER IO Urgent Research Task :	Yes
Experimental Approach/Plan:	Use the SPI and/ or MGI to inject impurities in an H mode plasma while applying a strong n=1 external phase using the I and C coils. Measure the IR footprint using the new IR periscope and the IR fast camera to determine the evolution of the footprint as a function of the phase and the intensity of the n=1 field.
Background:	Radiation assymetries induced by massive particle injection is a major concern for ITER. These asymmetries could induce local melting of the first wall if the toroidal radiation peaking factor reach a certain value. Injections at multiple toroidal locations are expected to mitigate this effect because it is assumed that the radiation asymmetry is due to the injection asymmetry. But recent results obatained by V. Izzo on NIMROD tend to show that these asymmetries could in fact be induced by a non rotating n=1 mode growing during the thermal quench and expelling heat from the plasma. The phase of that mode with respect to a massive particle injection would then determine the peaking factor.
Resource Requirements:	The SPI. Regular tokamak systems. Good beams availability. I and C coils
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Other Requirements: